Shinigami Koushaku no Yatoware Tsuma ni Narimashita ga, Kodomotachi ga Kawai Sugite Mainichi Shiawase desu!

Overview

Suzette, the daughter of a poor viscount, is falsely accused of infidelity by her fiancé and their engagement is broken off. Rumored to be a "villain" in high society, she is fired from the job she was working to support her family. Then she receives a proposal of marriage. Her suitor is the Marquis of Death, a notorious marquis who murdered his family to become head of the family! Suzette decides to get engaged to him for the sake of her family, but it turns out the marquis's mansion has two children she doesn't know about! A romantic comedy about a family-loving poor young lady and the Marquis of Death who enter into a contract marriage in another world! (Source: Kodansha, translated)

Source: AniList