Be honest.
If he's a decent guy, he'll be flattered at worst, and way more than that at best.
Similar advice as I gave to the OP - feel him out with questions first, check that he's not secretly madly in love with someone else. If that's not the case, suggest that you two spend some time together. If this is an internet thing - you'll have to meet.
If you are meeting him for the first time off the internet, make sure that you meet him somewhere where you have friends there, be it a party or whatever. Safety is important, and there are many people who can spin wonderful stories online who are horrid people. You can tell people you met the day before at a pub, it matters not what the story is, but put safety first. If he's a decent guy he'll more than understand. If he shows one tiny bit of hesitation at not wanting to meet you where there are other people around, well, i'd be suspicious to the point of moving on right there and then.