How do I make it clear that I’m not interested in someone?

Sad for her. :( She probably doesn't realize how uncomfortable she's making you, and I imagine it's because of her past experiences. Sounds like she doesn't respect your boundaries, though, so that really sucks for you. I would only suggest you be as clear as possible with her, and if she really doesn't relent, file a restraining order.

Fuck her best friend.

Good luck with that. If you figure out a way, let me know.

Tell her that you collect human teeth.

At this point I would say it's fair to be rude.

Tell her again and don't smile or act friendly. Then...stop all communication. Be clear, be firm, and then be silent.

I am convinced you are lying too.

Has there been anything between you that would suggest to her you are attracted to her?

Ignore her

You cant because shes delousional

Ignoring works.

Wow, that's unfortunate. TRO ?

Fuck her sister.