Yeah...you can't diagnose BPD in one hour. It's just not how it works. There are usually a lot of tests over a long period of time, the reason being that it's actually quite difficult to know whether someone has a PD. Sometimes a persons PD is quite mild so they don't have any 'noticeable difficulties.' My advice would be to check this persons credentials and actually question how they're able to diagnose such a complicated disorder in an hour. They can have a very good idea - be almost positive in fact, but the devil's in the details. If they don't seem to be on the level i would instead seek a referral to a PD team, people who regularly diagnose and treat PD's as part of their job description. Good luck, a lot of people struggle getting answers when it comes to PD's so just keep going and come back here for support.