He tells the bartender that he will buy her another of whatever she is drinking.
The bartender says "OK, I'll pour it for her. But just for your information, she's a hooker. She'll do what you want for money".
The drink gets delivered and the woman makes eyes at the guy, inviting him over.
After a couple of minutes of chatting, the guy gets up the nerve to ask her: "The bartender says you're a hooker, is that true?"
The woman says "Yes. I do it for the money. In fact, I'll do anything for $200".
The guy thinks for a minute and then pulls out $200, gives it to her and says
Spoiler:

