どうして（どうして）— why
どうして ですか。
Why is that?
どうしてどうして
why
どうして
accent [1]In detail
Words
どうしてdōshitewhy
ですかdesu kais it? (polite question)
どうして commonly asks why. なぜ is another word for why and often sounds more formal, though both occur in speech and writing.
Coco-sensei