Why don’t you try being honest and just tell her it’s obvious that you like her and would like to see more of her but that you are getting mixed signals. And just ask her right out if she wants to give things a shot with you.
I kinda have a feeling that she may be dating someone else, is in a relationship already, or is just really self centered and only cares about herself and what she has going on in the moment. Either way, being direct and honest will give you the answers you need. And you can either move on or keep at it.