err.. just experiment on it lng..
like tell a very corny joke, and see how he reacts.
or tell something that you just caught interest in all of a sudden that you think he has very little idea of,
and again observe how he reacts.
if he jumps on ur bandwagon right away, its pretty sure he has serious intentions with you. (or he could probably research about it afterwards and bring the topic up again if he refuses to react at first or keep silent lng for fear of appearing silly..

)
i don't know much about the games both of you play in the pre-courtship stage, but im pretty sure every other guy who has the hots, but most especially interest in the girl, would do what I have just described above. (in different levels of subtlety lng, coz of pride or ego issues.. so you have to be keen at ur observations in his reactions)
good luck, and bless your heart!
p.s. this is just personality we're talking about. if you wanna get serious with anyone for that matter, i would prize character (behaviour, habit, manners, etc.) much in the long run... as personality tend to change over time.
