Firstly, no a butt does not intimidate me. I'm not sure why you think that's the case, but a nice ass is a great sight to see...not an intimidating one.
Second, it all just depends on how the girl looks. Guys may have the stereotype that we're simple creatures, but even we don't just walk up and talk to your ass. If her ass makes her body look good, then it adds to the appeal of her and would make me want to talk to her more. But if we're talking about those massive, "ghetto booties", then no thanks. I like a nice, round ass...not a fat ass. There's a big difference.