One of my favorite D&D romance arcs involved a human paladin and a tiefling rogue in our campaign. Their dynamic was pure gold—initially distrustful due to racial prejudices, but slowly, the paladin's rigid morality softened as the rogue kept saving their hide with clever tricks. The turning point? A shared campfire scene where the rogue admitted they'd never been trusted before, and the paladin promised to 'be the first.' It wasn't flashy, just quiet moments of vulnerability between battles. The GM sprinkled in letters they exchanged during downtime, and by the finale, their kiss mid-battle against a dragon became legendary in our group.
What made it work was the slow burn. Neither character was reduced to a trope; the rogue still pickpocketed, the paladin still lectured, but their flaws became endearing to each other. If you're crafting a sweet romance, let it grow organically—shared trauma, inside jokes, and small acts of kindness (like the rogue 'borrowing' a holy symbol for the paladin's birthday) matter more than grand gestures.