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.
Nora RobertsHe loves me." "You sound surprised." "Nobody ever did. Not like this. It's easy to say, for some people. The words. But it's not just words with Roarke. He sees inside me, and it doesn't matter.
Nora Roberts