Everyone has their own ways to show it.
Heart is the part in my body that says if I love someone.
It is too hard to put in words,
but
Love = Caring about someone.
You want to defend the one you love.
You feel safe when the person you love is with you.
You would want to give evertyhing you can to her/him.
Even death can't separate you from her/him.

I believe it is this and much more than I can describe.