I think boundaries are important, since that also eliminates any potential hidden BPD traits. But I don't know, my ex was patient, self aware, a good listener, generous and kind hearted except when she was not. My parents, friends, etc. never knew her "other" side until our messy break up, they always thought she was this kind, generous and respectful woman for years.

Anyone can present themselves as a patient or generous person, especially BPD people. Now on I will be more interested in fine details and trust my gut feeling more. How they handle their emotions during though times are really important. Do they get angry easily or can they control themselves when things go wrong? Obviously, do they respect people's boundaries? But again, the devil is in the detail. I will look more into their behavior in specific situations rather than their version of themselves that they chose to show me.