I've seen this before as well...

You don't want to hurt his feelings, and that's completely normal. However, by leading him on and not being firm, you're only inviting him to continue the chase, which could lead to a worsened situation.

I've know friends who gave in and tried going out, leading to broken friendships and messy situations. If you've only been friends for a little bit, he may not be a true friend. He might have been trying to get you to like him during all this time, and is only interested in dating/sleeping with you.

In either case, be firm. Don't give in unless you like him too, and think a relationship would work. If he still pressures, start blowing him off (tell him you're too busy to hang out, this and that), and firmly tell him you don't like him in that way, and that until he stops trying, you can't hang out with him. This might be hard on him, but it's the only way you can remain friends. If her actually values you, he will understand