I just had a revelation, lol. About Sakura's confession, 540 and later, 573.
Sakura confessed Naruto, Naruto rejected her because of Sasuke. In 540 when she says there's someone else who... pause, the nin guys says, he must be a great guy, hope it works out for you, tra la la. Sakura thinks at Sasuke.
As I previously said, what if she thinks that it won't work out with that other guy BECAUSE of Sasuke, so that's why she thinks at him? What if, in 573, that part we're going to be together, no matter what you say, refers at the fact, she's going to be with him, no matter what Naruto says now regarding Sasuke?
In the end, the reason why Naruto rejected her was Sasuke, because he thought that she hasn't been moving from him, yet, she was saying she was and quite spirited. Kishi also enforces that. Not to mention, as I told you, she had no problem in calling him a criminal and glare at him when it came to Naruto's safety or Naruto's feelings.
Yes, she didn't killed him and she thought at him.
But what if those "I thought I could do it" and her crying was, indeed, a part of her not being able to, but also cying because she couldn't be of use to Naruto and failed to protect him. In her mind of course.
I think at this because as she said, "Naruto's resolve is way better than mine, I am supposed to be a ninja, yet I always fail" etc, something like that.
What if part of it, it was because she felt like she couldn't keep her promise to Naruto, of bringing back Sasuke?
Also, comparing resolves and how she wasn't ready back then, Naruto wasn't either until he had the clash. Afterwards, he was certain of what he had to do.
When the love letter nin came and said "hope it works out for you" what if, like I said, she was thinking at Sasuke because he's the reason things are NOT working out for her?
And now, with that we're going to be together, no matter what you say (Naruto's rejection), Sakura is ready to face Sasuke because after that love letter nin guy said, she realized that Sasuke IS the impediment in her and Naruto's way of working out?
What do you guys think? Does it makes any sense what I'm saying? I know my English sucks sometimes and now I'm writing on the hurry.
(edit: holy crap this is a lap. sorry!

I think I've had too much caffeine this morning! haha!)
I think the exact same thing. Since those chapters came out.
When Sakura confessed to Naruto, she was doing so in deed and in spirit. In words and with actions. So when people say they don't the very precise measure of her love for Naruto over Sasuke...I say it doesn't really matter anymore. She has chosen Naruto. She said she loved him, and went out to kill his best friend, the object of everything he does, so that Sasuke won't kill him or hurt anyone else. She's making the ultimate sacrifice, because she knows she's either going to die, or she's going to live and Naruto's going to hate her.
Only love would drive someone to make a fatal choice like that. And I don't see any of Naruto's other friends standing up to take the bullet for him. No one else even thinks about it. No Sai. Not Shikamaru. Not Hinata. Only Sakura.
And she doesn't talk about it, she doesn't try to drum up support. She takes it all on herself. (Which is exactly like Naruto, right?) And she could have had support if she wished. Naruto has friends everywhere now who would do anything for him. But Sakura didn't do that.
She chose to do the awful thing to protect him and keep anyone else from getting hurt. In a way that no one would ever know about. Either way, after this choice, she knew her life before was over: If she survived, she knew Naruto would hate her. Sai confirms this. So we can guess that, knowing Sakura, she would probably leave the village to make life easier for him. And the other option is that she dies, hopefully taking him down with her, as the precedent has been set in the manga with Minato and Saratobi. But either way, she has chosen this path which ends her life as she knew it. And she's done it all because she loves Naruto. And she tells him so.
I honestly don't know how people can question that kind of devotion. It's undeniable.
And her love and near-sacrifice is never undermined by Kishimoto going forward.
When she is saved, Kakashi says specifically to Sakura about Sarutobi not being able to kill his student. And that now he understood that love. That is a message to the reader that Sakura could not kill him because of her team bonds. Not love. Only the readers still believe she loved Sasuke, because it's never supported in the manga. Kakashi says he understands her, and gives us the explanation.
So later, when Sakura is confronted with another option, another love choice (lovernin), she easily says she already loves someone else. Because she does. It's Naruto. Without a doubt. So being interested in someone else isn't even an option. Her heart is already taken.
But when the lovernin goes on about her, saying that since she's great the guy must be great too, implying that she always makes good choices, Sakura reflects back that she doesn't always make good choices. In fact, she made an awful one that was causing pain to her and the one she loves.
I've always thought that Sakura felt bad about liking Sasuke, who turned out to
not be a great guy. And it also that she tied up Naruto with that stupid promise that was lie a curse, as Sai told her. But I like your idea that it may also be that she is reflecting back on her inability to stop Sasuke. She said she wasn't going to make any more mistakes, but yet she didn't follow through on what she said she'd do. So yeah, going forward, Sakura may feel responsible for any injury to Naruto from Sasuke, directly or indirectly. Just because Naruto saved her and tacitly smoothed over the rough patch from the confession so they could move forward doesn't mean that Sakura feels okay about not having accomplished what she set out to.
She was right in what she did then by trying to stop Sasuke. Because now the stakes are even higher. Naruto confirmed it himself. One or the both of them will die. And she was trying to prevent that by stopping Sasuke before he had a chance to kill Naruto. Her instincts were not wrong there. And she may have residual guilt because of it. She wasn't a damsel in distress, waiting to be saved. She was an assasin with a very worthy cause. So just because Naruto saved her doesn't mean her feelings for that failed mission have been reconciled.
Sakura is not Hinata. One hand-wave from Naruto's big, strong, safe hands is not going to make everything better for her.
Lastly, I really don't think Sasuke is a love impediment for her. I don't think
he stands in the way of NS. Other things do, but not some childhood crush on Sasuke. And I think Sakura has confirmed that with her actions. The motives of which have been confirmed by Sai and Kakashi. So she knows she loves Naruto. But everything else is more important right now. So she's letting it go until later. But when asked, she confirms it. Swiftly and without doubt. Yes, there is someone that she loves. This she knows.
However, as was seen Sakura's closeup panel in the last chapter, she has now seen that perhaps Naruto doesn't return her feelings like she thought. On the surface, Naruto and Hinata's interactions are intimate and close. Much closer than Sakura's ever been with Naruto, or vice versa. She's holding his face and looking into his eyes. Then he stands up and takes her hand.
Sorry, I don't care what country you're from — that's crazy intimate.
If you saw that from across a bar or across a classroom, you would totally think they were dating. Both in a mutually invested love relationship. Not just work buddies or chemistry lab partners. But dating.
So, I don't think Sakura's going to stop fighting to moon over Naruto's big, safe, strong hands holding someone else's. She's not Hinata. She's going to stay focused on the battle in front of her (something Sakura has in fact warned Hinata about in the past.) But I think her mental image of her teammate just shattered (ironically, just as Naruto's did before).
The idea has crashed down on her that Naruto may actually not reciprocate her feelings. And that doubt was foreshadowed in the confession. "If you don't like me, then just say so!" So from here on out, even though Sakura believes in her own feelings, I think she's a smart-enough cookie to know that Naruto has never confessed or confirmed his feelings to her...or anyone. He may actually like someone else, and his crushing response to her confession was a sign of that.
So I don't think Sasuke stands in the way of NS anymore, nor has it in a long time. I think the storyline has shifted to a true pairing-based conflict. Now I think Hinata is what stands in the way. And will until the very end when Naruto finally reveals his true feelings. Not his immature date requests. Not lamenting his unfulfilled promise. But actually says he loves her and hugs her back or kisses her forehead or show
her the affection, instead of the other way around.