Geuneun Nae Yeodongsaengeul Saranghaetda

Hildea Hillington, the daughter of duke Hillington, always knew that she was a mere supporting role in the story. She also knew that her destiny was to watch her younger sister, Roserielle, get married to young and ambitious duke Gabriel Velkius.
But something was definitely off. Why does Gabriel say that he loves me? He's supposed to be in love with my sister!

(Source: Pocket Comics)