I'm a Slave in an Alternate World but My Master Does Not Desire Me

Six years since she was transported to another world, Chika served as a pet slave for the strong and handsome knight Douglas. Normally, a pet slave would also serve her master in bed, but for some reason Douglas was not able to perform, so Chika still retained her virginity. It turned out that Douglas was traumatized as a prisoner of war by Chika while she was a prison guard disguised as a boy. Chika felt sorry for her master, but she prayed that he would never find out her former identity. As they spent time together, Chika's heart was touched by how Douglas treated her with wholesome kindness. Everyone could see that they were in love with each other, but will they be able to overcome their fears and misunderstandings and come to a happy ending? (Source: Kadokawa, translated)