Obviously, as we've seen through the series, Sakura is ashamed of her lingering feelings for Sasuke. She tells herself they don't exist and tries to push them aside. SO why, when the love letter nin proclaims his love, does Sakura immediately say "There's someone else I..."? She's obviously sure she has feelings for this certain person. That is why I think she was definitely talking about Naruto there.
Then we have chapter 540.
Mangareader translated Love Letter Nin's dialogue as "If it's someone that you like, then they're bound to be a great person."
I think that what he said could also be translated to "Anyone you would like is bound to be a great person." It doesn't really matter which one you prefer, my theory could work for both.
I think Sakura was reflecting on her past love and lingering feelings (I use this lightly because I am very sure she will get over him VERY soon if she hasn't already) for Sasuke and how he wasn't and isn't a great person.
Wellll that's how I see it anywayy lol
I like this explanation. At the very least, it's obvious the panel was a reflective scene. She's contemplating her lingering/former feelings for Sasuke, and they don't look very positive. Though, like Miss Soupy, I have a tough time accepting that she was talking about Naruto in 539. I think it's more so that her crush on Sasuke was/is so ingrained in her mind, she just sort of blurts it out without thinking. Maybe she was talking about Naruto, but I'd feel more confident if I saw more blatant evidence of that, at least in that particular scene.
But again, I'm not sure, since I admit I'm not that good at reading into these things. The only thing I am sure about is that the feelings Sakura has/had for Sasuke aren't being portrayed in a very positive manner. Throughout Part II the Sasuke/Sakura pairing has received nothing but negative development, in my opinion. And that reflective moment wasn't any different.
In any case, I hope this whole thing gets brought up again. I feel like that love-letter nin was thrown into the mix for a reason, other than just to remind his readers about previously established feelings. The context of the scene makes me think it's paving the way for Sakura to finally resolve that part of her character, now that she's seen first-hand what Sasuke's become, and knows how Naruto feels about her.

Edited by Boom...Winning, 24 August 2011 - 01:18 AM.