an idiom a week

The idiom for this week is:

the proof is in the pudding

Meaning: To fully test something you need to experience it. This phrase is just shorthand for the proof of the pudding is in the eating.

Origin: The origin of this idiom dates back to the 14th century.

A: I'm not sure if I should or shouldn't eat frog legs. I don't know if I'll find it tasty.

B: Well, I can only say the proof is in the pudding.