"You are my everything; I cannot survive without you."

The ultimate in tension. It requires a believable shift from genuine animosity to mutual respect and, finally, love.

that span the spectrum of gender and sexuality.

A breakdown of romance sub-genres like

Writing Romance 101 - Five Basic Elements - Almost An Author

From Fiction to Reality: How Storylines Shape Real Relationships

This is arguably the most popular trope in modern fiction. It provides built-in tension and a satisfying "thaw" as characters realize their preconceptions were wrong.