ㄴ다니까

I'm telling you, it does that

Says something again because you were not believed the first time: I'm telling you, he levitates; I'm telling you, that's nine hours; you're really good at guessing; I told you he'd be happy. The tone is insistent and a little exasperated, and it usually carries a rising note at the end. It attaches to present-tense action verbs; 다니까 covers descriptions and past forms, and 라니까 covers nouns.

Register: casual, insistent