12. You Can Just Tell
When a guy is in love with you and is falling head over heels for you, you can just tell!
Face it, he has that smile and all of the other signs of being in love.
He has that look in his eyes when he looks at you.
He sighs a happy sigh when he sees you.
And when he hugs you it seems like he never wants to let go and you believe it when he says "I can't believe how lucky I am to have you in my arms".
That my friend is definitely a sign that he is in love with you and that is why I put it at number one.