How do I get this girl to like me?

I know I've asked this b4 but I just did'nt get any answers so yeah. Anyway, I really like this girl [we're both bi] and I want to ask her out really bad. But she has a bf and I know she really likes him. We went out b4, but we broke up, by her choice. And I just really like her, and even if I can't be with her, I still want to get her away from the guy she's with. He's a cheating, pervy, man . And I'm not joking at all, he asked to fingure me yesterday and told me not to tell her. And I know he's just going to hurt her, and I want to get her away from him. But I think she MIGHT like me back. She always laughs at everything I say, and makes goofy faces and smiles at me when she sees me. And when I walk beside her she'll fallow me and leaves her bf behind her. But I'm not sure. I don't want to lose her as a friend, but I don't want to miss out on a girl like her. Either way, I just want to get him away from her so she won't get hurt. Advice, please?