But you don't have to do that. You can say, "No, I don't really want to give you my number because I don't know you and I don't think it would be appropriate." You didn't say anything to hurt him. You just protected you're right. That's assertive. The other is aggressive. There's a difference. You need to give yourself permission to be assertive to protect your rights without hurting somebody's else's feelings, and that means you've got to make a decision that you value yourself enough that you would protect yourself the same way you would protect a friend. Value yourself as much as you value a friend. Be you own best friend. It's real easy after you do it for a little while.