なぜかというと

Meanings

1

the reason is that ...; because

usually written using kana alone

Used to introduce an explanation or reason, often at the beginning of a sentence or clause. Functions as a conjunction-like expression.

なぜかと言いうと、昨日きのうは雨あめが降ふったからです。
The reason is that it rained yesterday.
彼かれが遅ち刻こくした。なぜかと言いうと、電でん車しゃが遅おくれたのだ。
He was late. The reason is that the train was delayed.