번역: I want/need you to do smth
what are the most common and natural Korean equivalents of frases below? does it depend on context much?
both in 반말 and in 존댓말, please!

I(we) want you(him) to do this.
I(we) need you(him) to do this.

감사합니다!I was asking to provide both 반말 and 존댓말, because sometimes the most common/natural grammar structures are different for each style.

Question

번역: I want/need you to do smth
what are the most common and natural Korean equivalents of frases below? does it depend on context much?
both in 반말 and in 존댓말, please!

I(we) want you(him) to do this.
I(we) need you(him) to do this.

감사합니다!I was asking to provide both 반말 and 존댓말, because sometimes the most common/natural grammar structures are different for each style.

Answer

I 반말(나)  존칭(저)
we 반말(우리) 존칭(저희)
want (원하다)
need(필요로 하다./해야 한다.)
you (너)(당신)
do(하다)
this(이것)
I(we) want you(him) to do this.
반말-나는(우리는) 너(그)가 이걸(이 것을)했으면 좋겠어.
존댓말-저는(저희는) 당신(그분)이 이 것을 했을면 좋겠습니다. 
I(we) need you(him) to do this.
나는(우리는) 너(그)가 이것을 해야한다고 생각해.
저는(저희는) 당신(그분)이 이것을 해야한다고 생각합니다.