Saishou no Ki wo Motsu Koyakunin no, Henkyou Nonbiri Slow Life: Shusse Dekizu Sasen sareta Hazu ga, Nazeka Mawari kara Tayoraremakutteimasu

Zen Leadon has worked in the central government for over a decade, always shuffled from post to post without any chance of promotion. Disappointed in him as a member of the esteemed Leadon family, his eldest brother Yohia demotes him to a post out in the countryside. A demotion like that would shatter anyone’s spirits...except for Zen’s. In fact, he’s over the moon with joy! However, that good fortune comes with a price. He’s suddenly tasked with the duty of sheltering the country’s princess—whose life is in danger—and acting as her father. And what’s more, that princess is the fourteen-year-old daughter of his first love. Will he be able to handle the new role that’s been thrust upon him?

(Source: J-Novel Club)