This is a tricky question to answer, as it's more about feelings than facts.
Love can be expressed in actions and words, though in the longrun actions are a lot more telling than words. After all, one muttered 'I love you' doesn't make up for the fact that your boyfriend is treating you in a non-loving way.
Love can be seen in his actions - does he treat you with respect and value? Do you feel genuinely cared for? Is he willing to compromise if the two of you are in a disagreement, or does he always need to get his own way?
Love is much more than love notes, sex, or little trinkets. If your boyfriend is there for you in hard times, and always willing to offer you support when you need it, then chances are he genuinely cares for you.