는데 Grammar is tricky
Hello :) , i hit really tricky grammar, which is '는데' .
I checked my grammar book and some free resources like TTMIK and i got certain view, but... it's tricky.
It's really easy to interchange 는데 with 그래서 and 그런데.( because of the usages and meanings ).
I was told that it sounds unnatural.

Please, can anyone make little review or explain in different way ?
( Maybe it's just matter of time, i feel that explanation provided by TTMIK is really good,
same goes for Korean Grammar in Use, but i am still kinda confused about it. )

Thank you :)
with regards
John

Question

는데 Grammar is tricky
Hello :) , i hit really tricky grammar, which is '는데' .
I checked my grammar book and some free resources like TTMIK and i got certain view, but... it's tricky.
It's really easy to interchange 는데 with 그래서 and 그런데.( because of the usages and meanings ).
I was told that it sounds unnatural.

Please, can anyone make little review or explain in different way ?
( Maybe it's just matter of time, i feel that explanation provided by TTMIK is really good, 
same goes for Korean Grammar in Use, but i am still kinda confused about it. )

Thank you :)
  with regards
       John

Answer

I'm also learning Korean. I learned 는데 from this website:
https://www.howtostudykorean.com/upper-intermediate-korean-grammar/unit-4-lessons-76-83/lesson-76/

I think he explains it really well. I really recommend this website in general. I don't know if that's what you're looking for, but I hope it helps :)

Answer

는데 is more like 'but/although' in a complex sentence. It can also be used as 'though'.
그래서 is 'therefore' and used in a more formal speech.
그런데 is also 'but' but you have to end the first sentence before using this word. It's also formal.

For example 
A: B야~ 밥 같이 먹으로 가자!
B: 난 돈 없는데... 
(Casual)

난 돈 없는데 A는 왜 자꾸 나 한테 밥 같이 먹자고 해?(casual)

저는 돈 없어요. 그런대 A씨는 저 한테 식사 같이 하자고 했어요. (Formal)

저는 돈 없어요. 그래서 A씨과 함께 식사를 할 수 없어요.

I hope it helps!