Doinaka no Hakugai Reijou wa Outo no Elite Kishi ni Dekiai sareru

Born with an unusual birthmark on her back, Chloe Ardennes was immediately branded a "cursed child" by her superstitious family and locked away in their estate for her entire life. Forced to cook and clean, Chloe's world shatters one day when an encounter with her mother at knifepoint drives her to flee the only home she's ever known. Desperately seeking refuge, she escapes to the only sanctuary she knows: the royal capital. But is the big city everything she hoped it would be? Just as she finds herself on the brink of despair, a mysterious, gallant knight rescues her, offering a glimmer of hope and the promise of a new beginning.

(Source: J-Novel Club)