Read manga Betrothed to My Sister’s Ex / ずたぼろ令嬢は姉の元婚約者に溺愛される / Zutaboro Reijou wa Ane no Moto Konyakusha ni Dekiai Sareru

With unmaintained red hair and shabby clothes, Marie, the baron’s daughter, has been treated like a servant all her life. Count Granado, the country’s richest man, who is said to be a difficult misogynist, falls in love with her at first sight. However, due to a misunderstanding, Count Granado proposes to her sister Anastasia, who looks like a princess, instead of the ragged Marie. A very popular work from “Become a Novelist”! Marie’s Cinderella story that began with a hero’s misunderstanding!
https://teenmanhua.com/manga/betrothed-to-my-sisters-ex