Question

무슨 이유로 그런 생각을 갖게 된거야? When talking about the negative consequence of a complex condition or situation (weather event, accident, illness, etc.), -(으)로 marks the reason of a (usually) negative outcome. In this usage, the particle corresponds to 'due to', 'because of', or just 'of'.

Accepted Answer

What put that idea in your head?

Front	무슨 이유로 그런 생각을 갖게 된거야?
Back	What put that idea in your head?
Notes	When talking about the negative consequence of a complex condition or situation (weather event, accident, illness, etc.), -(으)로 marks the reason of a (usually) negative outcome. In this usage, the particle corresponds to 'due to', 'because of', or just 'of'.

Negative 무슨 이유로 그런 생각을 갖게 된거야 Put