Suspecting my girlfriend of having for money?

hey guys, i have been dating this girl for 4 months now. in our second month she told me that a man that saw her in a club or smt and asked my gf's friend to hook him up with my gf. and that my gf's friend told him that my gf had a boyfriend. so he said, "at least let me have with her for $2000 she s so hot i cant get her out of my mind".... and my girlfriend told me that if i asked her friend about this we would fight and told me not to ask her or let her know that i know. the thing is that a week ago she decided to start a TV course and she needed 3000$ for it. she asked me for 1600$ and when i asked her where she would find the other 1400$ she said she had some money left that her ex bf gave her during their relationship... so what do you think? Realistic answers please i need help.