IMO you don't need to ask him BEFORE meeting him IF he is serious about you, or even serious about finding a committed relationship.. while he did say he is looking for a date or some fun, you never know what can happen when you meet someone amazing that you have chemistry with... he wouldn't be the first person who found someone amazing when they weren't looking (so to speak)
One date for a few hours out of your life wouldn't be time wasted right?
So meet him, see if theres a connection IRL... if you still like him and he you, then go out again... give it enough time before you write him off as not serious enough.
Good Luck