How do you make sure your girl is not using you?

I'm in university I have a model as gf with a good personality. I heard people saying my gf is using me for my money. I asked y you liked me she said because your talented in singing and dancing, got bball scholarship in bball. Now I feel happy and told people and then they said people can lie. She sometimes pays for the dates and get me stuff for my bday. One day she took 10,000 to buy jewlery. She said she sorry so do you guys think she is using me. BTW how do you deal with a stolen Cadillic Escalde