Saijoukyuu no Seijo Rashii desu ga, Ryuuou-sama no Hanayome ni wa Narimasen! Tsuihousareta node Yakushi toshite Dai Ni no Jinsei wo Oukashimasu

Countess Sophia grew up always treated coldly by her parents, who were partial to her younger sister. On the day of the Saint Selection Ceremony, her little sister was chosen, much to Sophia's relief. She felt as if a nuisance had finally been disposed of, and she decides that "From now on, I'm going to live my own life!" But just when she's about to start, the legendary Dragon King appears before her and says, "I've come to take you, a saint, as my bride." It's then that Sophia discovers that she is actually the "White Saint", who holds the strongest power of all saints. And all the while, Sophia leaving has grave effects on the kingdom's capitol city. Surrounded by her self-proclaimed husband and a sacred beast, Sophia raises medicinal plants, purifies the land, and has great success as a doctor... So what will happen when rumors about Sophia begin to reach the royal castle...?! Source: Starts Publishing