Sairin, whose status was lowered due to her late father's involvement in being arrested for treason, became the princess of Kihanabo. She tries to clear her father's name, but her purpose is discovered by the prince, Oren. However, he asks her for help in his revenge, and she ends up posing as his favorite concubine...? (Source: Kadokawa, translated)

Nobuko is a high school girl with a huge debt. One day, while looking for a lucrative part-time job, she meets a beautiful young man with silver hair on the street. As she stares at him, he suddenly hugs her, kisses her, and takes her to a different world! She is offered a high-paying part-time job in the other world with a job description: kissing, as he says kissing Nobuko fills him with power. Fooled by his sweet words, Nobuko decides to accept the offer and signs a contract... but his goal is world domination! A fantasy romantic comedy of the Demon King x extremely poor JK!

https://www.cmoa.jp/title/340700/