Best answer
저는 당신을 참 아름다운사람이라 생각합니다. (jeo·neun dang·shin·eul cham ah·reum·da·eun sa·ram·ih·ra seng·gak·hab·ni·da) = I think(believe) you are very beautiful person to me
미인(美人)이시네요(mi·in·ih·si·ne·yo) = you are a beautiful person 미남(美男)이시네요(mi·man·ih·si·ne·yo) = you are a handsom man 미녀(美女)이시네요(mi·nyeo·ih·si·ne·yo)= you are a beautiful lady
예쁘시네요(ye··bbeu·si·ne·yo) = you are pretty (normally to a female)
실물이 더 예쁘시네요 (sil·mul·ih deo ye·bbeu·si·ne·yo) = I guess you are more beautiful in reality = You are more beautiful than the photos
Slang 존잘(jon·jal) = really F handsome – for Boys only (very informal, only between friends) 존예(jon·jal) = really F beautiful – for Boys only (very informal, only between friends) 이뿨~ (eeh·bbppoua) = PRETTY~!
Answer
It”s hard to find an exact word to convey that aggressive sense of shock that WTF has but I”ll give a few that might work:
뭔 개소리야? (Mwon Gae-so-ri-ya?)
Meaning what dog-sound is this? Conveys the loss of words one feels when faced with some idiotic statement.
……ㅋ (……lol)
That passive aggressive lol seems to give off that sense of WTF although in a more sarcastic way.
헐 (Hul)
This is kinda of like that whoa or wat that we use when we”re surprised, and can be quite neutral. Use it in the right texting context or put in a deadpan tone though, and you”ll be able to hit the right image of WTF.
기가 막히네 (Gee-ga Mak-hee-né) or 어이없네 (Oh-ee Obs-né)
It doesn”t have that exact sense of shock WTF has, but rather the speechless aftermath after it. It”s basically words that mean ‘I”m so stunned by this stupidity in front of me that my energy has been stifled/I can”t speak’.
뭐야 미친 (Myo-ya Mee-Cheen)
Basically the two words ‘What is this’ and ‘Crazy!’. Closest to the the WTF I could think of, to be honest. Plus, you can always exchange the Mee-Cheen (crazy) in the back with ‘시발’ aka Shee-bal (A swear word that would give a more aggressive WTF) or ‘대박’ aka Dae-bak (An ‘amazing!’ that would give it a more OMG connotation to the WTF).