What happens when a woman asks if you have a girlfriend?

First, she may like you, but she is afraid that you have a girlfriend;

Second, she wants to know you. If you have a girlfriend to prove that you are still attractive, if you don't have a girlfriend, she thinks you have no feminine charm and can't be intimate;

Third, she may have an acquaintance girlfriend looking for a boyfriend;

Fourth, she may just ask casually and can't find a topic to chat with you.