When do we pronunce the "H" sound? 미안해요: mianHaeyo or mianNaeyo?
sometimes, i hear people say "i love you" in both "sarangHaeyo" and "sarangAeyo"
but for names, there's seems to have a specific pronunciation
희철: heechul pronounce as: Heechul
강호동: kang hodong pronounce as: kang Ho dong
민호: minho pronounce as: minNo(?)
은혁: eunhyuk pronounce as: eunYuk
sometimes they seem not to pronounce the h sound, anyone can tell me when should i omit it and when pronounce it?

Question

When do we pronunce the "H" sound? 미안해요: mianHaeyo or mianNaeyo?
sometimes, i hear people say "i love you" in both "sarangHaeyo" and "sarangAeyo"
but for names, there's seems to have a specific pronunciation
희철: heechul pronounce as: Heechul
강호동: kang hodong pronounce as: kang Ho dong
민호: minho pronounce as: minNo(?)
은혁: eunhyuk pronounce as: eunYuk
sometimes they seem not to pronounce the h sound, anyone can tell me when should i omit it and when pronounce it?

Answer

I think you are quite correct. 
'미안해요' has to be 'mi-an-hae-yo', but it sounds like 'mi-an-ae-yo' in conversation, 
so it's not your fault.:) 
But when you pronounce people's names, you should pronounce /h/ sound(ㅎ) exactly. 

Sometimes the /ㅎ/ sound can be weak when this sound comes after the vowel sound /ㄴ/ or /ㅁ/ like "미아+ㄴ+ㅎ+ㅐ요" as in "미안해요".