Are my feelings not appropriate for the situation?

I am wondering why you would ask her to begin with knowing she is alienating everyone else in her life. Pay the extra security deposit and never again depend on her for anything. She has made her bed, let her lie in it and don't trust her for a thing, ever. You will eventually get your deposit back of you follow the rules of the lease. Your feelings are appropriate but you made a mistake trusting someone who has a record of alienating loved ones and friends.