People are people, I am I. In the end...

"...I understand what Your Highness and everyone are trying to say." The Duke's daughter Caroline looks at her fiancé before her, and the young lady standing beside him. She understood. And she had already taken countermeasures. Then she also knew what to do next... ※I've added the villainess tag, but this is not the typical comeuppance story. ※There is almost no romantic element.