Urareta Henkyou Haku Reijou wa Ringoku no Outaishi ni Dekiaisareru

Anna, daughter of the Margrave of Halmich, rejects the traditional role expected of women in court and instead trains in swordsmanship, hoping to one day fight alongside her father. When the Kingdom of Albion invades and captures her brother, she is exchanged for him, being sent to the enemy prince. Despite the hardship, Anna remains determined, aiming to use her position to infiltrate the enemy and avenge her father's death.