는다는데

'They say X — so / but…'

-는다는데 relays what people say and leaves it open for whatever comes next: 무섭지, 잡귀가 붙는다는데 'of course it's scary, they say spirits latch onto you.' Several lines here quote proverbs this way — 말 한마디에 천냥 빚도 갚는다는데 'they say a single word can repay a huge debt.' The speaker is passing the claim on, not vouching for it.

Register: casual spoken