but, however, and

그렇지만 – but, however / 그런데 – and 

피곤해요. 그렇지만/그런데 영화 보고 싶어요 – I’m tired but I want to see a movie.  
어제 이거 샀어요. 그렇지만 정말 커요 – I bought this yesterday but it’s really big.  
어제 이거 샀어요. 그런데 정말 커요 – I bought this yesterday and it’s really big.