Sihanbu Heungmang An Guhago Tteonamnida

Reborn into the life of a maid in a novel, Betty has one goal: to live a quiet and unassuming life. Unfortunately for her, at the end of the original novel Duke Janus ends up annihilating the world. Now, Betty must try to change the story and escape from the duke, who is growing ever more obsessed with her.
(Source: Manta)