Jonah 3:10 proves 2 important things:

1. Turning from your evil ways/sins is WORKS.

2. Repent DOES NOT mean stop sinning or turning from sin, because God repented and does not sin:

And God saw their works, that they turned from their evil way; and God repented of the evil, that he had said that he would do unto them; and he did it not.
(Jonah 3:10)

ℝ𝕖𝕡𝕖𝕟𝕥𝕒𝕟𝕔𝕖 𝔼𝕩𝕒𝕞𝕚𝕟𝕖𝕕