Translation guide
Expressing that something is definitely true or will definitely happen. Japanese often uses adverbs, sentence-ending particles, or set phrases rather than a single noun equivalent.
The speaker wants to assert that a fact or statement is undoubtedly correct.
Adverb meaning 'certainly' or 'surely', often used to agree with a statement or acknowledge a fact.
Certainly, that is correct.
Adverb meaning 'without a doubt' or 'definitely'. Stronger than 確かに.
Without a doubt, he will win.
Phrase attached to nouns, adjectives, or verbs meaning 'must be' or 'no doubt that'. Expresses strong conviction.
He must be sick.
Colloquial phrase meaning 'it's obvious that' or 'of course'. Used in casual speech.
That's obviously a lie.
The speaker wants to convey that something will definitely happen.
The speaker wants to check if something is certain or to express doubt.
Pattern meaning 'whether or not'. Used to embed a question about certainty.
Referring to certainty as a concept or quality.
English 'certainty' as a noun is rarely used in natural Japanese conversation. Instead, use adverbs like 確かに or 必ず, or phrases like に違いない to express the idea.
必ず implies a natural or logical inevitability, while 絶対に is more subjective and emphatic. 絶対に is common in both positive and negative sentences, but 必ず is less natural with negatives.
There's no certainty that he will come.
Formal; in conversation, 彼が来るかどうかわからない is more natural.
Adverb meaning 'without fail' or 'definitely'. Used for future events or obligations.
I will definitely succeed.
Adverb meaning 'absolutely' or 'definitely'. Often used with negative for 'never'.
Please definitely don't forget.
Phrase meaning 'should be' or 'ought to be', based on logical expectation. Less absolute than 必ず.
He should have arrived by now.
Please check whether he will come.
Simple phrase meaning 'Really?' to express doubt or seek confirmation.
Really? I can't believe it.
Formal noun meaning 'certainty' or 'reliability'. Used in technical or written contexts.
The certainty of that information is low.
Noun meaning 'conviction' or 'firm belief'. Often used in the phrase 確信がある (to be certain).
I am certain of his innocence.