Is it normal to have a "friend" like this?

I have a "friend" who is an asswhole to me but when it comes to needing help, she's there to help. I don't know if thats what you call a "true friend." Another factor to consider is how she is just a good person who likes to do good things so I feel like when I need help and she helps she is only doing it to be a good person not because she actually wants to help me. When it comes to just hanging out or whatever she is an asswhole. Always poiinting out the negative things about me, never has a real conversation because she is always joking around, makes these faces at me, etc. So at the end of the day, I don't consider her as a "true friend" even if she helps me when I need it. I think that's just a part of her nature. And the worse thing is she is a good person but not to me in general so if I complain about her to others, they won't believe me because she doesn't treat them like she treats me.