What would あなた do if あなた know your best friend is letting あなた down?

If あなた don't get what I mean... My friend is going to tell another friend about another guy 読書 my personal texts. But he 発言しました he will never speak of it again. But she thinks she feels guilty when she doesn't understand that my other friend will lose trust on me.

(I'm sorry if I'm too confusing, hard to mention what's happening)