Unmei no Noroware Ouji to, Mahou Gakkou de Futatabi Koi ni Ochiru

When Sofia was a child, she promised her future to the prince. She only found out after they were no longer able to see each other, but he was now a distant memory. "I must somehow meet him one more time and put an end to my feelings." So she resolved to aim to become the top student at the magic school, which would give her an audience with the prince! But at that time, the prince was also...!?

(Source: Kodansha, translated)