Only through actual experience can the value of something be tested. A proverb. He was intrigued by the ads about the new high mileage sports cars. "Drive one, sir," the salesman said. "The proof of the pudding is in the eating."
PROOF OF THE PUDDING IS IN THE EATING
Meaning of PROOF OF THE PUDDING IS IN THE EATING in English
American idioms English vocabulary. Английский словарь американских идиом. 2012