Hi, Grace. I'm sorry to hear about your problem. I can understand your feelings. I'd be glad to give you some advice.
First of all, say sorry to Rena because you told someone else some personal things about her. And you should promise her that it won't happen again. Then you could prepare something nice for her. Maybe you can send her some flowers to show that you're truly sorry. Also, it might take some time for Rena to forgive you. During this time, if you don't have anything nice to say, don't say anything at all.
I really hope my advice will help you, Good luck!
Kate Hawking