Grace of the Vineyard

After the death of her mother, Ruby is taken in by her mother's friend, Mrs. Watson, as a maid for the Bell family. She meets Grace, a young lady of different origins. She thinks she's just a bad girl, but Grace is the only one in the Bell household who cares about her. She becomes the only one who cares about Ruby, and a strange feeling grows between them...

Ruby's feelings for Grace are either envy or love.

(Source: Lezhin, translated)

Note: Chapter count includes a prologue