Proof entered English in the 12th century as Middle English prove, prooff, prof, proufe, with the meaning “evidence sufficient to establish a thing as true.” It finds its roots in Late Latin proba, meaning "a test." An example of proof meaning “test” is in the English proverb “All the proof of a pudding is in the eating,” first recorded in English in 1605. The proverb is popularly but wrongly attributed to Miguel Cervantes. In the second part of Cervantes’ Don Quixote (published in 1615), Cervantes wrote “Por la muestra se conoce el paño,” literally, “From the sample you know the cloth,” which was translated into English as “The proof of a pudding is in the eating” by Peter Anthony Motteux, a French-born English playwright and translator, in his English translation (third edition 1712). We know this today as the saying “The proof is in the pudding.”

Did you mean proffer?