Verified answer

The sentence would have been perfect if you'd put a space.

"담배 안 피기로 했잖아!"

Also, "담배 끊기로 했잖아!" works pretty well.

If you have any further questions about your Korean sentences, pleas feel free to email me. I'd be more glad to help editing Korean.

Yes, it's right.

It's the shorter version of “네가 이젠 담배 끊는다고 했잖아!”/

"네가 이젠 담배 안 피운다고 했잖아!"

The missing part is "You said you were going to" part, but doesn't make a big difference.

"담배 끊기로 했잖아" would be better I think

quit smoking = 담배 끊다

but your sentence is good too :-)

its correct!

maybe