An Incompetent Woman Wants To Be A Villainess ~The Young Lady Who Married As A Substitute For Her Stepsister Didn't Notice The Duke's Doting~ summary:

Avril is a young woman of exceptional ability who was mistreated and labeled "incompetent" by her family. Avril marries into the family of an "old, lustful duke" in place of her half-sister, but the duke, Dylan, is actually a beautiful young man who is the complete opposite of what he is rumored to be. He wants to marry a "villainess," and a contractual divorce her after three years is perfect for Avril's future freedom. The people around her are bewildered by the mysterious "brilliant woman" who plays the role of a "villainess" with gusto, but they are gradually drawn to her...