The Lost Lady and the Crimson Duke

Justine, a down-on-her-luck noblewoman, had her engagement annulled and exiled from her estate after she was falsely accused of stealing her fiancé's family heirlooms. Four years later, she is once again falsely accused of theft at the royal court, where she has been working as a seamstress under an assumed name. Justine was about to give up hope when she is rescued by the king's nephew, Duke Simeon. But for some reason, he insists on keeping her at his mansion until she is cleared of all suspicion? (Source: Sankosha, translated)