The Housemaid (2011)

Eun-yi (Jeon Do-yeon), a poor Korean woman, takes a job as a domestic servant in the lavish home of Hoon Goh (Lee Jung-jae), a handsome businessman whose wife Hae-ra (Seo Woo) is pregnant. Under the tutelage of her new boss, longtime employee and familial confidant Byung-sik (Youn Yuh-jung), Eun-yi quickly learns the ways of the house -- and that Hoon's word is law. But when Eun-yi allows Hoon to seduce her, the benefits of her new position become dwarfed by the consequences of her actions.