The simple and most complex answer is love.

She gazed toward the marsh that grew thicker, deeper, greener with approaching summer. Mosquitoes whined in there, breeding in the dark water. Alligators slid through it, silent death. It was a place where snakes could slither and bogs could suck the shoe right off your foot. And it was a place, she thought, that went bright and beautiful with the twinkling of fireflies, where wildflowers thrived in the shade and the stingy light. Where an eagle could soar like a king. There was no beauty without risk. No life without it.

I didn't get fired." "You didn't punch your boss and get fired from the Tribune? That's what I heard." "I punched what could loosely be called a colleague for cribbing my notes on a story and since the editor–who happened to be the asshole's uncle–took his word over mine, I quit." "To write books. Is it fun?" "I guess it is." "I bet you killed the asshole in the first one you wrote." "You'd be right. Beat him to death with a shovel. Very satisfying.

Action, reaction, motivation, emotion, all have to come from the characters. Writing a love scene requires the same elements from the writer as any other.

Don't you want me to kiss you goodbye, sweetie?" "Kiss a cow farm boy

You all right?" Diana let out a deep breath. "Ask me again when I'm not praying.

If you’re looking for the full deal, the till-death deal, then look at me. No one’s ever going to love you, stick by you, understand how you work the way I do. (Malcolm Kavanaugh)