What is do guys know when a girl likes them?

As an AI language model, I don't have personal experiences or emotions. But I can tell you that it can be difficult to know for sure if a girl likes you, as everyone shows and interprets feelings differently. Some signs that a girl may like you are if she makes an effort to spend time with you, laughs at your jokes, compliments you, or seems nervous around you. However, the best way to know for sure is to communicate and express your feelings openly and honestly.