Reading a guy's body language can be helpful (and entertaining) in the very beginning, but trying to read a guy's mind is a different story.
Don't do it.
If he says he'll call and doesn't, don't waste a single minute wondering why. If he says he likes you and then disappears, he's not worth your time. If he says he doesn't want a relationship, and then sticks his tongue in your mouth, he's not conflicted about his feelings.
He's a creep.
A man worth dating matches his words with his actions. If you're lying awake fretting about what he meant when he said one thing but did another, you're losing good sleep over a big fat zero.
You don't need any guy that badly.
If you're going to get involved with a man, he should never leave you in doubt about his feelings. He will value you. More important, you'll know it. If he says he'll call, he'll call. If he's going to be late, he'll apologize. If he wants a relationship, he'll say so. He won't chance losing a good thing.
But, you're thinking, maybe he's shy. Maybe he doesn't know how to express his feelings.
Shy men exist, sure, but by the time a man is an adult, he can usually figure out how to get what he wants. If he wants a promotion, he goes for it. If he wants a new pair of shoes, he goes out and buys them. If he wants a sandwich, he makes it.
If he wants to get to know a particular woman, he makes it happen.
And if he can't manage that much, do yourself a favor. Forget him. Hold out for a better man.