Can you convince a friend she has borderline personality disorder?

Why do you want to?: What is your reason for trying to convince her? How will that help her? You probably just need to be her friend, not her therapist. There could be consequences to your attempts, like she may resent it. Often times, unsolicited advice doesn't go over so well. If you don't like her personality, why associate with her? If you enjoy her company, maybe just try and accept her for how she is.