のは簡単じゃないよ

it's not easy to

→ の
phrase Rare #38,599
it's not easy to Follows a verb phrase to say that doing something is not easy. The final よ adds emphasis or indicates the speaker is informing the listener.
JA: 新しい言語を習うのは簡単じゃないよ。
EN: It's not easy to learn a new language.

体重を減らすのは簡単じゃないよ

Losing weight isn’t easy.

恐らくそれをするのは簡単じゃないよ

It probably won’t be easy to do that.

ウサギ素手で捕まえるのは簡単じゃないよ

Catching a rabbit with your bare hands isn’t easy.