KyoZaNa✿'s Manga

For some reason, she isekai into a novel as Cordelia, a side-character who has both name & looks same as the Saintess. Thus she'll get mistakenly kidnapped by the villain, Duke Valencia then get killed later after he finds out the truth.
To avoid that pitiful fate, the 8-years old girls runs away from the orphanage and by chance meets up the collapsed villain and somehow ends up saving his life.
The villain not only wants to adopt her but also wanna raise her to be the Saintess!? Oops..
악당의-소중한-따님

Due to her self-indulgent, frivolous, and immoral behavior, Madam Bianca was thrown out of Arno family after death of her husband, Count Zachary. She had nowhere to go, since the Blanchefort family have already fallen to ruin. Later the villainess with no honor died on a cold stone floor at a convent. -- That was Bianca’s life before she went back in time.