Well, sappy or not, I liked it. Teenagers tend to doubt themselves in affairs of the heart and I think you've played this perfectly. Teenage love rarely survives in the long term, people move on, but in some cases and this would be one where your best friend for years is also your love interest, it'll work. JKR missed the boat on that one, since her own life was so messed up until she met Mr. right. Ron and Hermione? Puleeze! That was never going to work. Harry and Ginny? What did they have in common? They would have wound up drifting apart.
Author's response
I'm willing to accept that Harry and Ginny might have been able to work--primarily because I just didn't learn enough about Ginny during the books to really be able to gauge how compatible she and Harry would be. I didn't like that she said she "never gave up" on Harry, though. What does that mean--she never gave up on her hero-worship of the Boy-Who-Lived? Meh. It wasn't a well-written romance, but I can accept it because, like I said, I just don't know enough about Ginny to feel confident in saying she wouldn't be good with Harry long-term.
Ron and Hermione, though? I completely agree. They spent years seemingly constantly arguing with each other, and their personalities appear to clash horribly. I don't think JKR could have picked someone less suitable for Hermione if she'd tried. I don't dislike Ron (aside from when he's being a stubborn jerk, that is), but I just think he and Hermione are all wrong for each other.