Hmm. As you say, I doubt the landlord is going to take your side.

She sounds like a spoiled brat. I know you want to keep things tidy, but she's not going to help. I know it's not easy, but if you must stay there, then just try to ignore her. Don't let her manipulate you, too. And certainly don't clean her bathroom! You are not her mother. Maybe someone else has other ideas, but I'm wondering if just pitching her messes into her bedroom might help when you are having company over. And/or let it be known that she is the slob! My son has roommates who also don't clean up after themselves.

If things keep bothering you too much, then I do suggest you try to see what other places might be available. Please don't let her bring you down. On second thought, you might try having a heart-to-heart with her first--telling her you both need to work together, trying not to sound judgmental. Maybe tell her you like her and want to get along, but her behavior is distressing you. Maybe do that before just assuming she won't do better.

I'm wondering if you know much about her past. How does her boyfriend deal with her?

Wow, what do you other folks here think?