As you're experiencing, relationships with a pwBPD are emotionally intense. Additionally, the skills and tools that can make those relationships "workable" are
not always intuitive.
In "broadly normal" relationships, reassuring a partner of our love and commitment is pretty straightforward and effective.
However, by definition, BPD is a disorder. It's a fundamental difference in how some brain wiring works, not just a transient issue of "not enough information" or "lacking an insight" or "once they have the facts, things will be better".
So, what that means is that because you're here looking for what to do, and you're on the "bettering" board, you may want to consider trying some non-intuitive skills and tools.
A specific example would be here:
I kept reassuring her that I know thats not how she truly thinks of me and that I won’t leave
In a "broadly normal" relationship, reassurance, promises, and understanding may be "okay" or "work".
Those really, really won't be effective in this situation.
pwBPD have higher-than-normal needs for validation, and especially for
not being invalidated.
We are trying our best to be loving and supportive, yet our "normal" efforts can make things worse, by inadvertently being invalidating.
When telling her that you knew that wasn't what she really thought...
that was inadvertently invalidating.
It basically told her "what you think is wrong".
Now, I'm not suggesting that you lie, or agree with misperceptions, if she has them.
What I am suggesting is that inadvertent invalidation makes things worse by "missing her emotional point".
I wonder if you can now, sitting here, hear the emotions behind her words. Her words were:
I hate you, I don’t want to be with you, You’re not what I want... Im not special and not worth it.
It's so tempting to reply
to the words with "But I know you really love me, and you're SO worth it, I love you so much".
The emotions going on under the words, though, are incredibly important.
What do you think those emotions are?
And how might you validate those?
For example, if an emotion behind the words is "I feel worthless", a way to validate that feeling might be "Babe, that would feel awful to feel that way".
Check out this post on not being invalidating:
https://www.bpdfamily.com/content/communication-skills-dont-be-invalidatingand let us know your thoughts on this.
I'm kind of "pushing this hard" because I hear you that there's a lot of hurt going on and you'd specifically like some help with figuring out what to do.
-kells76