ખરા ન ખરાનાં પારણાં ધીંગાણે.

kharā na kharānāṁ pāraṇāṁ dhīṁgāṇē.

Literally: The test of the true and the false is in the battle.
What it means: A person's true character is revealed only when they are put to the test.
The English proverb Shah set beside it: The proof of the pudding is in the eating.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1923) · read from the scan by machine — the Gujarati itself is unchecked · English is machine-made and nobody has checked it yet

Heard it differently, or know we've got the sense wrong? Tell us — that is exactly the kind of correction this needs.