回复：why not just ask him to be

Frist, he does not only want to do sales with me together, but also wants to join the design team with me. He think my product is great, but can be greater if he join in. He has designing experience but not sales experience. His design ability is greater than me. I am thinking this is ok, as long as we can work well together(there is something I can bring to him, and something he can bring to me). But we have never worked before, that is why I post the question.