the reason is that ...; because
Used to introduce an explanation or reason, often in response to a question or to clarify a preceding statement. Similar to なぜかというと, but slightly more casual.
See also: なぜかというと
He didn't come. The reason is that the train was delayed.
なんでかというと、それが一番簡単な方法だからです。
Because that's the easiest way.
Phrase composed of なんで (why) + か (question marker) + というと (when you say). Literally 'if you say why it is', used as a fixed expression meaning 'the reason is'.