Translation guide
This guide covers how to express that something is guaranteed, certain, or assured in Japanese. It focuses on natural expressions for promises, certainty, and conditions, rather than direct translations of the English word.
Expressing that someone has guaranteed something, often in a commercial or personal promise context.
Means 'comes with a guarantee'. Used for products or services that include a warranty.
この製品は1年間の保証付きです。
This product comes with a one-year guarantee.
A somewhat old-fashioned or literary verb meaning 'to guarantee' or 'to assure'. Not common in everyday speech.
成功は請け合いだ。
Success is guaranteed.
Expressing that something is inevitable or bound to happen, without implying a person's promise.
Means 'must be' or 'no doubt'. Used when you are very sure about something based on evidence or intuition.
彼は来るに違いない。
He's guaranteed to come. / He must be coming.
この計画は成功するに違いない。
This plan is guaranteed to succeed.
Indicates a strong expectation based on reason or logic. 'It should be that...'
彼なら知っているはずだ。
He's guaranteed to know. / He should know.
Adverb meaning 'without fail', 'definitely'. Can be used to emphasize certainty.
間違いなく雨が降る。
It's guaranteed to rain.
Adverb meaning 'always', 'without exception'. Used for things that are certain to happen.
Expressing that one thing is guaranteed if another condition is met, often in rules or logic.
Means 'as long as'. Used to state a condition that guarantees a result.
ここにいる限り安全だ。
As long as you're here, you're guaranteed to be safe.
Means 'if only you do...'. Implies that doing that one thing guarantees the result.
ボタンを押しさえすれば動く。
It's guaranteed to work if you just press the button.
The English word 'guaranteed' is often used loosely (e.g., 'It's guaranteed to be fun!'). In Japanese, 保証する (hoshō suru) is more formal and implies a concrete promise or warranty. For casual certainty, use patterns like 〜に違いない or 必ず instead.
努力すれば必ず報われる。
If you work hard, success is guaranteed.