For me (as in others may differ) love is something I feel for my pets, for children, best friends and family, etc I care what happens to them and would go above and beyond to see no harm came to them, nurse them back to health, give them the shirt of my back, etc.
Being in love is all of the above and then a step further. You have that lust, passion and ability to look into their very soul. It is as if you are intertwined in a sense knowing what they're thinking or how they will answer a question. There is a trust, respect, and connection that is like no other and the moments when you look in each others eyes and you know with all your heart and soul, your in love. A gift that is to spectacular to foresee.