는걸요

Polite 'but I did / it is, you know'

-는걸요 makes a soft objection or a mild boast while staying polite: 하지만 할머니 저는 너무 낡고 지쳤는걸요 'but grandma, I'm too old and worn out.' It concedes and disagrees at the same time, which is why it rarely lands as rude. It is -는걸 with 요 on the end; drop the 요 among friends.

Register: polite, gently contradicting