자기 = his/her own thing while 자신 = himself/herself/yourself examples : 그는 자기 몸을 좋아해요 = he likes "his own" body 어머니는 자기 딸을 믿어요 = The mother trusts "her own" daughter 저는 제 자신을 믿어요 = I believe in myself if you use 자신 to mean oneself you can use 자기 before it too for example ; 그는 자기 자신을 믿어요 = he believes in himself *********** I'm learning korean too , I hope you understand what i said ! good luck !!