Uruwashi no Koutei Heika no Tsugai ni Erabarete Shimatta no desu ga, mada Shigoto ga Shitai node Himitsu desu!

The court pharmacist, Tianna, devoted herself daily to her work in order to save people. Just as her efforts were recognized and she received a promotion, a "special mark" appeared on her body. It was a sign that she was the "fated partner" of Emperor Safir...!? While the search for the bride was underway throughout the entire court, Tianna, who only wished to continue her work as a pharmacist, decided to conceal her true identity. However, to her astonishment, Tianna was appointed as the personal pharmaceutical assistant to the exceedingly busy Emperor Safir... (Source: Overlap, translated)