てみせるDo it and prove it; demonstrate
てみせる expresses a strong commitment to carry an action through and prove it by actually doing it. It can also literally mean performing an action so that someone can see or recognize how it is done.
A commitment proved through action
In the determination use, the speaker does more than announce a plan: they commit to achieving the result and proving that commitment through action. It is especially natural with controllable actions and emphatic cues such as 必ず or 今度こそ.
Determination
今度こそ、必ずこの交渉をまとめてみせる。
This time, I will definitely bring these negotiations to a successful conclusion.
Analyze今度こそ and 必ず make the pledge especially forceful.
Literal demonstration
The same form can retain its literal sense: someone performs an action so that an observer can see the action, ability, or result. The observer may be stated directly or simply understood from the situation.
Doing something for others to see
料理人は客の前で魚を鮮やかにさばいてみせた。
The chef deftly prepared the fish in front of the customers for them to see.
AnalyzeThe setting makes this a visible demonstration rather than a pledge about the future.
Choosing among similar forms
Use てみせる when actual performance will serve as proof or demonstration. てみる means trying something to discover the result. てやる can express determination too, but is rougher and more defiant, while つもりだ states an intention without the same promise to prove it through action.
More examples
必ず期限までに試作品を完成させてみせます。
I will make sure the prototype is completed by the deadline.
Analyze何度失敗しても、最後までやり抜いてみせる。
No matter how many times I fail, I will see it through to the end.
Analyze彼女は笑顔で「一人でもやり遂げてみせる」と言った。
Smiling, she said, “I will get it done even on my own.”
Analyze手品師は空の箱から花を出してみせた。
The magician demonstrated the trick by producing flowers from an empty box.
Analyzeこの折り方なら、私がゆっくり折ってみせましょう。
For this fold, let me demonstrate by folding it slowly.
Analyzeコーチは新しい投げ方を選手の前でやってみせた。
The coach demonstrated the new throwing technique in front of the players.
Analyze