If you are writing a love story, consider whether your characters have a relationship relying more heavily on one or the other, then emphasize that. If you are wanting to write a story that is about love (rather than just plain erotica), make sure not to overemphasize passion.
If you are talking about real life, it's important to remember that in the best relationships, the two usually go hand in hand. Sincerity of love is edified by passion. Don't settle for one without the other.