Reitetsu Hakushaku wa Kegare o Miru Meido o Hanayome ni Nozomu Umarekawaru nara, Anata no Soba ni

The story is set in the late 19th century in Britain. Paula, a young woman who lost her mother early and suffered harshly in a poorhouse, has a special ability. Thanks to a unique vision, she can see "impurities"—the germs of disease, malice in people's hearts, and impending death—which has helped her survive. After being sent out to work as a maid at age 14, she leads a modest life. One day, her employer transfers her to a ruined mansion with a terrible reputation, to work for a man rumored to be a "Dark Earl". There, she meets the enigmatic Selwyn, the Earl of Roseberry.
https://www.cmoa.jp/title/334858/