[Rivière]

It's very understandable to you're upset with your friend. After all the time you'd spent confiding in her, I can only expect it to feel like somewhat of a betrayal to find that your best friend is talking to the very person who'd raped you, especially since she was especially supportive of you over the situation.

However, and this isn't to say I'm defending your friends actions, but sometimes there are a combination of reasons why people forget things, even things that can be a big deal. For instance, depending on how long ago the incident was, the guy comes across as nice and polite and as you've mentioned and that she's going through depression. Therefore as much as she tries her best to provide you with support, there may have been a moment in time where she'd got a little caught up in her personal life to think about how anyone else was doing or what had happened to them. These may not seem like valid reasons, but they are and there are times where we all forget things regardless of their severity.

I think the best thing you can do, if you feel you want to get things straight with your friend, is to talk to her. Again I understand how it must feel to have someone tell you they forgot what had happened to you, but you won't know why she forgot unless you chat with her and find out if there's something going on with her that she hasn't yet mentioned.

If/when you've chatted with her and you feel her reasons were/weren't good enough, then it's up to you to make a choice in whether or not you want to continue chatting with her.