I Can't Escape the Cursed Duke's Doting Affection! ~The Substitute Bride Was Actually the Strongest Spy~

Rina, an elite spy, infiltrates a duke's household disguised as a maid accompanying the bride for a mission. However, when the bride runs away, Rina herself is forced to become the bride. She flawlessly plays the role of a bride, but her husband-to-be, a "cursed" duke's son, becomes increasingly obsessed with her as he seeks an heir. A dangerous undercover romance unfolds as Rina struggles between her mission and love.