Gaengsaengbulga Heungmakgaui Saeeommaga Doeeotda

After dying in an accident, Leona wakes up in a novel as the third stepmother of the story's future villainess, Rebecca Petry. As Duke Ian Petry's only child, Rebecca is resentful, rowdy, and rebellious, terrorizing those around her. The duke orders Leona to raise his daughter, and she rises to the challenge, but the little girl is a formidable foe. To preserve the family's peace, Leona uses childrearing knowledge from her past life, but will she be able to turn this rugrat into a little lady?
(Source: Tapas)