Sakura really hasn't killed anyone yet in the manga. The only person she really fought was Sasori and we can all agree that he wasn't really human in the end anyways. Sasuke definitely has something to do with it but killing ANYONE in general would probably be difficult for her in the end.
I just don't get, why people think that Karui Would suddenly fall madly in love with Naruto. Naruto had loved Sakura since he was a kid it would be stupid for Kishi to do that.
Because this world is filled with people who think using jealousy to spawn a relationship is a good idea... -.-;