I am sorry on what happened on you. Based on my experience, those with "charming" personality are most likely those who tend to suck up on other's secrets for juicy gossip. I am so sorry to say this... I doubt she will keep her mouth shut even if you told her so.

What should you do? Learn to analyze who are the ones you can trust and share your secret with. If they like to gossip around and share other's secrets to you, never trust them. One of my method is to give them one non-so-confidential secret about me. If that secret somehow get their way to other's ear, that's the red flag. I hope this helps you.