Listen to My Heart(2011)

Original title: 내 마음이 들리니?

This is the love story of Cha Dong-joo, a man who's been rendered deaf after an accident but pretends he can hear, and Bong Woo-ri, a woman who's intelligent but pretends she's dim-witted to protect the dignity of her mentally disabled father. She has been looking for her step-brother, Bong Ma-roo, who ran away from home 16 years ago. What she soon finds out is that Jang Joon-ha, Cha Dong-joo's brother, is Bong Ma-roo himself.