Disguised as a Man, He Still Chose Me (Season 3)

Top modern assassin Sylvia Lockwood dies and wakes up in the body of a woman with the same name. Her father fell on the battlefield. To survive in the Lockwood Family, her mother has disguised Sylvia as a boy since birth. Sylvia wants to become a woman again, but fears she'll be killed if her disguise is exposed. She plans to run away, but instead catches the attention of Valerian Blackwood, the cruel and powerful ruler of the Aethelgard Kingdom. After being taken to his residence, Sylvia must match wits with Valerian in order to survive.