This girl. and I have been on 4 dates and were good friends for a long time and I know her ex hurt her. We are to the point where we cuddle, kiss eachother whenever we say bye to eachother, go out together alone regularly, and admit we like eachother. Now its to the point where I asked her when she is ready to consider making it official and she said I still need some time to learn to trust me and know I won't hurt her. How long is too long to wait for her?
Do something to make her forget about her ex. Something that her ex would never do for her. It doesn't have to involve a lot of money, most women dont like to be spoiled with money, the prefer to be spoiled with a great time. So take her to someplace exiting to her. Somewhere that her and her ex never went to. The key is to let her know that your nothing like her ex. Hope that helps.
Too long is when you feel like it's not worth it anymore and you're better off finding someone else. You should definitely give her a chance since it's hard to struggle with trust issues. However, there's a limit. At a certain point it just feel like their trust issues are something they should work out alone/with a therapist, and not while actively trying to get into a relationship (because that could just make things worse). So yeah, be with her for as long as you want. And when you get tired of it, leave. That's about it.