What's in a BPD diagnosis? A very limited amount of real information.
Borderline disordered people will lie to you. They'll only tell you what they think you want or need to hear. They'll project their own bad behavior onto U, and make YOU out to be the bad guy.
People with BPD traits are afraid of attaching to another. This is why they act-out by pushing you away or picking fights, right after you've shared close, intimate-feeling episodes.
Borderlines are highly manipulative, hyper-controlling and possessive. They separate you from family and friends, so you have no clear and rational frame of reference for what you're feeling, in response to their hurtful or confusing behaviors (who ya gonna call?!).
A borderline disordered lover will frequently contradict him or herself. Their story keeps changing, because there's no real basis for TRUTH in what they tell you. You can believe NOTHING of what they say. This means, when they say "I hate you!" it has no more validity than when they say, "I love you!"
People with BPD traits are INCAPABLE of loving. Oh, they act, sound and appear like they actually love you (at least, at the start of your romance)~ but the more emotionally available you ARE to them, the faster they find fault with you and drop you on your head.
A Borderline will TEST you constantly, to see how much torment and conflict you'll put up with, just to "prove" to them you really love 'em and care. Problem is, the Borderline is a bottomless pit of need. They have NO frame of reference from infancy onward, as to what genuine adoration FEELS like, so they have no baseline by which to measure Your devotion and affection for them.
Borderlines pay close attention to what you appear to want, and orchestrate their behaviors and things they say to you, to MATCH your desires, wishes and priorities. In short, they morph into whatever it is they sense you WANT, and become that to seduce you into thinking you've "finally found (your) soul mate."
People ask if the Borderline "knows" they're doing this stuff. They wanna understand if all these manipulations are deliberate and consciously plotted. For the most part, the answer is No. Seducing you comes as naturally to a Borderline, as breathing. Their seductive behaviors are automatic and reflexive~ not necessarily premeditated.
Desperate people do desperate things. Someone incapable of impulse control, empathy (not to be confused with sympathy) or a healthy sense of boundaries is a survivor. The Borderline's ability to SURVIVE is all that matters. YOUR survival matters not to 'em, so concern for Your well-being doesn't show up on their radar, unless you're being manipulated into thinking it does, when it serves their own agenda.
These aspects are typical within the BPD framework, but they're only the tip of this iceberg. You won't find a thorough explanation of the Borderline Personality's complexities in the DSM-V or any other materials you read online about this diagnosis, because 99% of the people who WRITE about BPD have never worked successfully with it.
My website articles on this topic have garnered world-wide acclaim however, and thousands have written or called saying, "It's like you've been a fly on the wall, watching everything that's gone on in this relationship with my BPD lover, and it's uncanny that you've been able to describe it all in such specific DETAIL!"
Well, yah. When ya work with thousands of people who live with poor self-worth, emotional dissociation, and fear of bonding with another, you get to know the organism pretty frigging well.