Trapped in a Secret Room With the Magnificent Duke

After finishing an ordinary day and falling asleep, she woke up to find herself locked in a secret room with the handsome duke. In the middle of the room lies a parchment stating that if she doesn’t have s-x with Duke Gerard within the time limit…. He will die. ‘Why, oh God, must you give me such a trial?’ The only way to escape is to jump at the sleeping Duke. “Is the important thing Lady referring to, ugh, mounting my unconscious body, moaning, and moving your hips?” In a desperate attempt to save the Duke, she ended up tying up his hands and lunged(?) at him while grinning and bearing it. Afterward, tormented by guilt, Reyna finally seeks him out… “I will formally submit a marriage proposal to the Count Hendrick family.” But for some reason, the Duke declares he wants to marry her. What could be the secret behind the room that trapped them?