Youhei Kizoku to Fuujirareta Mahou Otome

Ito was expelled from the Academy of Magic, even though she was at the top of the class. She now spends her days doing odd jobs in the infirmary of a mercenary troop. Lara Stein, a handsome mercenary who always acts grumpy because of a "craving for magic," always clashes with the serious Ito when he comes to look for painkillers. However, they end up making a promise to help each other, which will require them to make intimate contact on a regular basis...!

(Source: Love Coffre, translated)