How do you know if your boyfriend means it when he says he loves you?

You will know that he loves you if you have been going out for decent amount of time. Unless its love at first sight(: Now all guys are different. Some will look very confident and just flat out say it. some will open up buy saying 'I'm really nervous' or look shaky when they tell you. Tone of voice is also something to look out for. If they sound like they have been working up the courage to tell you, or if they have been awaiting that moment their whole week you can automatically tell that they most definitely mean it. If they say it and it sounds out of habit odds are they weren't being honest with you. After he tells you that he loves you say something like "I won't be mad if you don't mean it, I just want you to be honest with me" if he didn't mean it he might say "okay, thanks." but if he did mean it he will say "No, i do I'm serious. I love you!" Hope this helps(: