how do you know when a guy isnt just saying i love you just beacause?
You can know if a man genuinely loves when he couples up his talk with deeds. You can always tell from his body language as well as the facial expressions. Check out http://www.ehow.com/how_4506826_guy-loves.html for more information.
you could try and test him see how he reacts
You can't honestly there will be no way to tell if he's lying or not unless he's very bad at hiding it
Guys love through their eyes girls through their ears. his version of the meaning of this word is so different than yours.