Kyuutei Nyokan Myeong-Hwa Taiyou Miya no Kage to Unmei no Ouhi

Lee Myeong-Hwa, the daughter of a fallen family, works hard as a seamstress, despite being bullied by her superiors. One day, she meets a handsome military officer at the palace and, without knowing why, ends up spending the night with him. The next day, she is ordered to become "Seigun Court Lady" (a candidate for the king's concubine)...!? The king's doting love will make your heart skip a beat! A fateful Korean fantasy!

(Source: Flex Comic, translated)