Ok my best friend been with her boyfriend for 2 years now, recently they've been fighting and kind of breaking up and starting again, now when they have a fight she comes to me and tells me all about it and we've grown closer.

I'm starting to have feeling for her more than friendship and I think she's starting to feel for me. So how do I tell her how I feel without making seem like I want to take her off him? Or should I just keep it to myself.

Keep it to yourself, telling her how you feel is stupid and immature. Wait until she's single and, I can't stress enough, over her ex. Only then should you morally be allowed to tell her.

Keep it to yourself as mostly what you think are love, is friendly gratitude at having some one to talk about her problems with.