The Crown Prince's fiancée has amnesia.

Amelia, the Duke's daughter and fiancée of the Crown Prince, always seemed to accumulate fatigue beneath her constant smile. It was not difficult to imagine that Crown Prince Richard would rage like wildfire if Amelia stopped her devotion. He would absolutely not tolerate her interfering with his actions either. For example, even her simple wish that he stop his flamboyant womanizing before marriage. Even if she were to become Crown Princess, Amelia seemed far removed from happiness. After suffering through a high fever, she had forgotten everything. ※There are no schadenfreude elements. [Also published on other sites]