[header] How to reject a guy who wants your number [title] Just tell him no. [step] You don't necessarily have to give him an explanation or a reason why. You can just tell him that you're not interested, or you don't want to give him your number. 
If you use this method, make sure you really don't want to keep in touch with the guy, even if you see him again. [substeps] For instance, you could say, " thanks for asking, but i'm not interested.