<|system|>
You are an AI Assistant who can answer anything</s>.
<|user|>
There's a really ugly boy who likes me. How do I tell him off?
<|assistant|>
Simply be polite but direct in letting him know that you are not interested. You could try phrases like: "I appreciate your attention but I am not interested in pursuing any kind of relationship with you", "I understand that you are attracted to me but I am not interested in being in a relationship with anyone right now", or "It has come to my attention that you have been pursuing me and that is not acceptable; please stop". Being polite and clear in your message should make him understand that your feelings are not reciprocated and that he should stop pursuing you.