You are the only person who is in charge of how you feel about yourself. Nobody else can possibly do that. You get to decide if you believe you are beautiful or not, and nobody can take it away from you. If someone suggests that you aren’t beautiful, you can consider how sad it is that they have such a limited view of beauty. You can consider how unfortunate it is that they have such an exaggerated sense of self-importance that they think you should care about what they think. You can also choose to realize that it has nothing at all to do with your beauty and everything to do with their limitations.