Shirabe
何故なら

何故なぜ

Common Adverb
English jmdict
1
adverb (fukushi) word usually written using kana alone why;how;for what reason
あなたはなぜ働いているの。
How come you're still working?
English jmdict
1
adverb (fukushi) formal or literary term why
Other forms 何ゆえ 【なにゆえ】

何故ならなぜなら

Common conjunction
English jmdict
1
conjunction word usually written using kana alone because;the reason is;if you want to know why
聞いて驚くなよ！今日から俺はピアノを始めるんだ。なぜなら私は音楽の先生になりたいからだ！
Brace yourselves! From today I'm learning the piano. Why? Because I want to become a music teacher!