Question: It's the question that all girls ask,...

you are right it is dificult t

I recently found a guy via facebook that I was friends with 15 years ago. Back then I was interested in him as more than a friend, but he ended up dating my then best friend. Well, now, after talking and hanging out, we are now dating. So, sometimes it just takes time!

You can't "get" a guy to like you as more than a friend. There are things you can do to help your relationship become stronger if it starts out in a platonic fashion, increase communication and become more intimate with each other (not necessarily in a physical way, but more emotionally and mentally.) If the things that you wind up expressing during that wind up piquing a guy's interest, then he might show signs of romantic interest. If all else fails, you can always be up-front and bring up the discussion with him, but if he says "no" then that's that.
The thing about most men is that they are pretty adamant and decisive about what they like and what they don't. While some men would not mind a casual fling/physical relationship this might not be what you want, so you shouldn't try to seduce him. Like you, a guy probably has at least somewhat of an idea of what he's into, and if you don't fall into that category, there's not a whole lot you can do about it without becoming dishonest.
If the issue of "ruining the friendship" comes up, then there might be issues in your friendship too.

The bottom line is be honest and sincere: strengthen your friendship and if you feel like your friendship is solid enough to bring it up without making things awkward, then don't be afraid to.