I recently read the manga chapters where Sakura confessed to Sasuke, the Promise of the Lifetime and the last few chapters of Part 1 (I never read those parts in the manga before, I remember watching them solely on the anime, but it has been years). Reading those chapters made me reconfirmed certain things that I already knew, and KIND OF proves, or at least supports, certain speculations I have.
1) Sakura really DOES love Sasuke, and I still think she does. I kind of figure it was a no brainer, but I see people arguing about Sakura's feelings about Sasuke. Reading her confession to him made realize that she did love Sasuke, as she says she was always happy around him (though I think she was talking about being a part of team with him, and may have been talking about Team 7 itself, but she singled him out). Like what Sai told Naruto after he figured out that he loves Sakura ("You always smile when you're around her..."), and what Hinata said to Naruto during her confession to him (something about always being happy when he's around, didn't reread her confession, though I think I should read all the 'potential' pro-naruhina moments). But during that whole confession, she never gave me a good reason why she should be in love with Sasuke. At least for Naruto it has been IMPLIED he had other reasons to like her, other than her looks, and Hinata fell in love with Naruto because of his determination. Which leads me to my first speculation...
2) The bench scene IS important, and it CAN be the reason why Sakura is in love with Sasuke. They were at that bench when she caught him leaving, and she brought up the time when he called her annoying. She also mentions that that was the day they became Team 7, but weirdly doesn't mention the part where 'he' (really Naruto) comments on her forehead and they nearly kissed. But what was sad to me, what really got me, was that she claims she will be alone if he leaves and tells him that she'll make him very happy if he chooses to be with her (it didn't matter if he left the village or not, she was wiling to go with him). It really got to me because I felt incredibly bad for Sakura, as she really believes that she will be alone without him. This actually reminds me about the average teenage girl, who feel like having a boyfriend means everything, and, for those who felt lonely, made them feel less...alone. But if you think about it, she was actually being incredibly selfish in her confession. She didn't want him to leave not because of his own sake, but for her own. She didn't want to be alone again, so she begged him not to go so that she wouldn't lose him and to not feel lonely again. That made me sad too, not only does she believes she's alone, but the fact that she believed that Sasuke was the one that prevented her loneliness. But I believe if you ask most fans, especially fans on this website, about who was more there for Sakura, they'll say Naruto. Oh, and the bench scene could still be very important in how Naruto can win her over. Cause if that whole day, where they first became Team 7, was really important to Sakura (and she even mentions SPECIFICALLY the time Sasuke called her annoying), then won't it make sense that it will still be important for her for other reasons (like the day she believed she started loving Sasuke). Naruto even remembers that time he pretended to be Sasuke, as it was shown, in flashback, that Naruto was recalling the time when Sakura told him (Sasuke) that she wanted him (Sasuke) to accept her during her confession to him. And if you believe it has been to long for that to still be important, remember that Sakura's confession to Naruto was in the 470s, and recently Kurama joked with Naruto about the time he kissed Sasuke, which happen in the same chapter (3). The joke happen around 570s, and if we are lead to believe that complimenting the aspect of a girl that even she doesn't like is ONE of the things that will make her fall in love with you, then would it make sense that Sakura fell in love with the wrong person because she believed he was the only to like the aspect of herself that she hated the most (her forehead).*
3) The Promise of the Lifetime was to sort (remember it being longer in the anime), and doesn't really sell the fact to the audience that Naruto is in love with Sakura. Don't get me wrong, it was implied, STRONGLY implied ("I understand how you feel about Sasuke, I feel it too."). But it wasn't as emphasized, nor as obvious, as Sakura's confession to Sasuke, in which she yells at him that she loves him and doesn't want to see him go. And even though Sakura's crush on Sasuke was selfish (or "naive"), at that point we, the audiences, figured that Sakura has grown to really love Sasuke (evident when she cried for him when she saw him in the hospital, and later made more obvious in her confession). We weren't, at that point, have been given a good reason of how or why Naruto is in love with Sakura. We know what he will do for her (save her from Gaara, and then make the promise), but we haven't been reasons, or at least not obvious reasons, of why he should been in love with this girl. So really, when he makes her that promise, I can see why people may not believe he did it because he loved her. But because she was his friend, and couldn't keep his original promise that Sasuke will never leave. Though you can see there is sadness coming from Naruto, not only on the fact that Sasuke has left and Sakura is begging him to bring him back, but he actually does seem little bit sad about the whole Sakura loving Sasuke thing. But really, even though I understand people missing that the first time, by the time summit arc hit and Sai tells Sakura that Naruto loves her I think people should have realized it by now.
4) I understand why people may believe that series will end Naruhina and/or Sasusaku, because I PROBABLY would have also believed that the series was going to that direction. Now don't get me wrong, at that point I would prefer Narusaku being the endgame, cause of the whole Promise of the Lifetime thing. But that's the direction was heading to because 1) Sakura's crush has been a lot more emphasized and she did seem to love him, and 2) Hinata still has a crush on Naruto, and was the last one to see him off. At that point, it seemed like an all win situation, Naruto just needed to let go of his feelings for Sakura, or for those feelings to never be brought up again. Also, like I said above, Naruto's crush has never seemed as obvious as Sakura's "naive" crush on Sasuke, nor as Hinata's crush on Naruto. In fact, in Part 1, the main character traits for both of those girls was their crushes. People (me included) saw Sakura as a Sasuke fangirl, thus those people would have believe that Sakura will become his girlfriend. Hinata was introduce as the shy girl with a crush on the main character (and she still is that), thus people would assume she will get her shyness and end up being Naruto's girlfriend. Naruto was NOT introduce as the guy with a crush on Sakura, and people seem to always want to be reminded about his crush for them to believe that Naruto is in love with Sakura (or for him to still be in love with her). Actually though, if it was just the love triangle between Naruto, Sakura and Sasuke (it's not really a triangle, more of a line), then I don't think there would have been so much debate about Narusaku becoming cannon, because it was just the triangle then it would be obvious that Naruto will win. But no, we have the Naruhina possibility, which will provide an all win situation where everyone gets paired together. Oh, and Hinata became stupidly popular afterwards.
*I felt kind of silly typing that down, because I didn't want the bench scene to become important in how Naruto wins her over, but I'm cool if it only leads her in realizing that she never really loved Sasuke romantically. At that point I want her to be already fully in love with Naruto (meaning she has no doubts), and the bench scene will just make her let go of her feelings for Sasuke.
^Here's a LONG comment I made about Sakura's confession to Sasuke.
I bring it up again as an answer to this. v
I have question, why do people always say that Sasuke is not the same person that Sakura fell in love with anymore. When did Sakura every had a good reason to fall in love with Sasuke, like said before Sakura's love for Sasuke is shallow, naive, delusional, and abusive. We have some sense of why Naruto loves Sakura and before Hinata's confession, we knew why she loved him, but for Sakura we got nothing.