Silsuro Namjuui Dongsaengeul Kkosyeobeoryeotda

Wait, why are you in love with me?!
An office worker is reincarnated as Elena, the villainess of a romantasy novel. Aware of what fate awaits her, she rejects the male lead's offer to become his lover and thinks herself safe from trouble. That is, until she discovers that she has unwittingly charmed the male lead's younger brother!
(Source: Manta)