What do I do to repair the relationship with my ex-best friend?

About 3 years ago, I was talking about my best friend behind her back because I was mad. She found out and we made up after this. Soon after a very unreliable source told her that I was messing with her step-father (of all people) I couldn't even believe that she would believe something like that. Its so far from the truth and I felt like she should know me better than that. I tried to talk about it to her right after I heard about the allegations but she refused to talk to me. So now its been all these years and for some reason I feel like I should try to talk to her about the whole thing. Should I make the first move? What do i say?