My friend won't give up.?

I have a friend who believes he's perfect for another one of my friends. His name is Adam. My other friend, Amy, thinks he's weird. She is tall, has gorgeous red hair, slim, a great singer, smart, funny, a pretty face. She's every guy's dream. Especially his. Now, she's probably the most humble and sweet girl I've ever met. She's told Adam that he needs to back off, to leave her alone, everything. He won't give up. How do I convince him to let her go? Because I've already sat him down and told him. That didn't work. He has no chance of being with her, and I don't want him chasing after Amy anymore. I don't want him to be hurt, and her to be completely creeped out. Help!