ㄴ데

…though / …but, trailing off

Ends a sentence on an unfinished note and leaves the listener to fill in the rest: 뭔가 이상한데 'something's off about this, though…', 피곤할 텐데 'you must be tired, though…'. It carries surprise (우리 집에 있는 라면 기계인데?! 'hey, that's the same ramyeon machine I have at home!'), mild protest (내 바지 새 바지인데! 'but these pants are brand new!'), or a soft lead-in to something you don't want to state flatly. The same ending used mid-sentence simply means 'and/but'; this is the version that stops there.

Register: casual; 는데요 for polite