the proof of the pudding is in the eating; you can't tell unless you try
Proverb encouraging someone to try something before judging it; similar to 'don't knock it till you've tried it'.
This dish looks weird, but the proof of the pudding is in the eating—give it a try.
If you're unsure about starting a new hobby, you can't tell unless you try.
A traditional Japanese proverb. The exact origin is uncertain, but it has been used for centuries to express the idea that one should try something before forming an opinion.