What is when she calls you handsome?

As an AI language model, I do not have personal experiences or emotions. However, if someone calls you handsome, it generally means that they find you physically attractive. It could be a compliment on your facial features, grooming, or overall appearance. It's a term often used to express admiration or affection. Depending on the context and tone of the conversation, it could also be seen as flirty or teasing.