Shinigami to Reijou

Yulia is the beautiful daughter of the Duke Anker, but she has the reputation of being a haughty and cold-hearted "villainess," which caused the Fourth Prince to break off their engagement. Instead, she gets married to the widowed Marquis Winkler, a man with the fearsome nickname of "The Grim Reaper."

(Source: Comic ZeroSum, translated)

Note: Originally published as a short-story in vol. 14 of the anthology "Akuyaku Reijou desu ga, Shiawase ni Natte Misemasu wa!"
https://www.cmoa.jp/title/354310/