to be honest, the truth lies in what she has done, not what she has said in the past. Seems to me, it's likely she uses the best friend phrase loosely. by her actions in no way does she think of you as such. No, especially when it comes to women, the true best friend of someone is always very involved in big things like a marriage..

I dont' know if you should talk to her about it. Depends on what you expect to get out of it. my guess is that she would be oblivious to the idea that she'd done anything to hurt you. I think she's likely a superficial person that puts on a face for people all the time. Superficial coming from the fact that she met someone online and after not a very long time, she is marrying him. Something's not quite right in all of this..

Just my take.