그 사람이 결혼한다니, 말도 안 돼

The line, explained

Every drama has this scene. A friend drops some news over coffee, the heroine's cup stops halfway to her mouth, and she repeats the news back as if testing whether it is real. Korean has an ending built for that moment: -다니. It takes what you just heard and holds it up to the light in disbelief. Today's line is the first reaction to hearing that an old love is getting married, and it shows how Korean grammar can carry shock without any exclamation word at all.

그 사람이 is 그, "that", 사람, "person", and the subject marker 이. Koreans often say 그 사람 instead of a name when the person is emotionally loaded: an ex, a crush, someone they would rather not name out loud. 결혼한다니 starts with 결혼하다, "to marry". To use -다니, first turn the verb into its plain statement form, 결혼한다, "he is getting married", then attach -니. The comma that follows is the beat where the speaker's breath catches.

말도 안 돼 is one of the most useful phrases in Korean. 말 is "words, speech", 도 is "even", and 안 돼 is "it doesn't work, it can't be". Literally "it doesn't even make words", so "that makes no sense, no way". Put together, the line says: "He's getting married? That can't be." English needs "I can't believe"; in Korean, -다니 already does the not-believing, so 말도 안 돼 simply doubles down on it.

The shape of -다니 follows the plain quote. Action verbs in the present take -ㄴ다니 or -는다니: 간다니, 먹는다니. Adjectives take -다니 directly: 춥다니, 예쁘다니. The past takes -았/었다니: 떠났다니, "he left?!". Nouns take -(이)라니: 학생이라니, "a student?!". The mood ranges from delighted surprise, 합격했다니! (you passed!), to outrage, 나한테 거짓말했다니 (you lied to me?). Tone and the next sentence tell you which; the ending itself just means "to think that".

Swap the news and keep the gasp: 떠난다니 (he's leaving?), 돌아왔다니 (he came back?), 날 기억한다니 (he remembers me?), 거짓말했다니 (he lied?). Notice how 돌아왔다니 and 거짓말했다니 use the past, while 떠난다니 is present. You can also turn -다니 on yourself with the dictionary form: 내가 이런 말을 하다니, "to think I would ever say this". That self-directed version is a favourite in confession scenes, when a cool, guarded character finally admits they have fallen for someone.