The Fae King's Deadly Bride Episode 18

Orphaned by fae soldiers, Vesper, the last dragon, enters King Rhyad's Bride Trials with a blade for his heart. She falls for him and cannot kill him. Named queen anyway, she kills her cousin Laros when he attacks Rhyad, then confesses her mission, and fae law demands her death. Rhyad kills his own commander to save her, but when she learns she has cost him his crown, she flees and leaves him to decide whether to reclaim her.