Yawareta Princess

Penny-Rose, a stone mason in the Principality of Castaliae is summoned by the Queen. She asks Penny-Rose to marry the prince... but only for one year. To succeed the throne, the prince needs to marry a woman of "unimpeachable virtue". Startled by such a sudden request, Penny-Rose hesitantly accepts. Despite knowing he is to marry another after her, she is slowly drawn to the prince, and eventually falls in love...

(Source: Jmanga)