Love is vulnerability. And faith.
Mostly when you get to know someone romantically there are layers of armor between you, because both of you are only extending enough trust so as to avoid getting stabbed should the other decide to pull a knife, figuratively speaking. We can get hurt emotionally far more deeply, and lastingly, than we can get hurt physically, and so we take care to protect ourselves.
Love is that point where you look into her eyes, and you make that decision deep down to take off the armor because being close is more important than being safe. Love is when its more important to be vulnerable, than to protect yourself. Its where you place such a deep trust in another person that you create that potential for them to strike you in the most vulnerable place, because you honestly believe that they could no more do it you than you could do it to them.
Love is kissing your sweaty, stinky, flu-victim wife when she looks like hell and has crusty stuff in the corners of her eyes. Because its
worth it.
Dangerous voodoo. Not to be taken lightly.