I cannot give my own opinion without more details. There are way too many factors to consider when asking if not helping someone is right. In the case of abuse, I believe you need to protect yourself from that person.
Personally, if she is sincere about getting help, and needs you to assist her, then I would encourage you to help her if you are able to do so without harm to yourself. Part of her disrespect could be her inability to manage her own feelings due to her personality disorder. I wish I could give a cut and dry answer, but often situations like this are so complex, you would need to talk with a counselor in order to know what the best course of action you should take.