conditional N4 common casualpolitewritten

のなら — if ~ (given what you say)

のなら

Builds on なら

Meaning

if (it's the case that) ~ — picks up something just said or evident and responds to it

そんなに行いきたいのなら、行いけばいい。

If you want to go that badly, then just go.

Attaches to	Form	Example
Plain-form clause	[clause(plain)] + のなら (often shortened to のなら → なら)	行いく → 行いくのなら

疲つかれているのなら、少すこし休やすんだら？

If you're tired, why not rest a bit?

買かわないのなら、もう触さわらないで。

If you're not going to buy it, then stop touching it.

彼かれが来こないのなら、私わたしも行いかない。

If he's not coming, then I won't go either.

In speech のなら frequently contracts to んなら (行いくんなら) or collapses back to plain なら.

Jengo shows のなら the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.

Sources Compiled with reference to A Dictionary of Advanced Japanese Grammar.