How do you say "no" to someone who asked you out but they are really sensitive? (see details)

Well, the other day someone asked me out and he also asked if I could go to the formal (prom) with him, but I do not want to go with him or out with him because I do not like really sensitive guys and I don’t have any feelings for him at all.
I could use some help on this, both guys and girls please.