Reading your man's body language could explain his feelings. When his body language becomes less playful and more intimate and protective, there is a greater chance he is falling in love with you.
Men tend to talk about things they have some sort of passion for. Many will talk predominately about themselves. Once he starts talking more about you, his feelings are probably leaning toward love.
Spending Time Together
Men will generally tend to spend more time with women as their feelings turn into love. If a man wants to talk to you several times a day and wants to see you as often as possible, even going so far as to rearrange his schedule for you, chances are he's falling in love.