Migawari de Totsuida Reikoku Kokuou wa Hatsukoi Aite deshita

28 years old, single, and without a boyfriend, Kanae Yano's life changes forever when she is suddenly summoned to another world! There, she's greeted by Duke Zach Skrein and his daughter Rita, a noblewoman who looks just like her. They plead with Kanae to take Rita's place as her body double and marry King Eugene Eistalotte, a cruel dictator feared as the "Cold-Hearted Wolf." Since the summoning magic is unable to send her home, Kanae has no choice but to accept. But when she finally meets the King, she discovers his true identity... A fantasy romance about reuniting with a first love begins!

(Source: Square Enix)