物(もの)は試(ため)しthe proof of the pudding is in the eating, the proof is in the pudding, don't knock it till you've tried it

物(もの)は試(ため)しだ、とりあえずやってみよう！

"Don't knock it till you've tried it, let's give it a shot for now!" {the proof of the pudding is in the eating, the proof is in the pudding, don't knock it till you've tried it}

物(もの)は試(ため)しなので、やってみないと分(わ)かりません。

Since you never know until you try, you should give it a shot. This is similar to the English saying, "the proof of the pudding is in the eating." {the proof of the pudding is in the eating, the proof is in the pudding, don't knock it till you've tried it}

実際(じっさい)にやるのを怖(こわ)がっている人(ひと)に物(もの)は試(ため)しだと言(い)った。

I told the person who is afraid to actually do it that 'the proof of the pudding is in the eating'. {the proof of the pudding is in the eating, the proof is in the pudding, don't knock it till you've tried it}

物(もの)は試(ため)しでやってみたら失敗(しっぱい)したが、これは経験(けいけん)となります。

I tried it out as the proof of the pudding is in the eating, and I failed, but this becomes experience. {the proof of the pudding is in the eating, the proof is in the pudding, don't knock it till you've tried it}

社長(しゃちょう)：「成功(せいこう)するかわからないが物(もの)は試(ため)しだ、よし、やってみよう！」

President: "We don't know if it will be successful, but the proof of the pudding is in the eating. Alright, let's give it a shot!" {the proof of the pudding is in the eating, the proof is in the pudding, don't knock it till you've tried it}