Responses
I mean....Hyo-Un had been lying to him and working for whatever reason. WE know, but Tae doesn't. He's literally one second away from locking Hyo-Un up bc he's thinking g the worse right now--meaning he's wondering if Hyo-Un is cheating on him or he's wanting to leave. Couple that with Hyo-Un dropping to his knees and babbling, when he finally asks Tae to marry him, of course Tae is caught off guard. That's where that, "What?" comes from.
Why he said what ╥﹏╥ ¿? Please accept the proposal TT