Expressing Strong Certainty in Japanese: Kitto, Kanarazu, and Mou Tashika
Learn to say 'definitely', 'certainly', and 'sure' in Japanese using kitto, kanarazu, and related adverbs, and understand how they differ from possibility words like tabun.
By TheaFirst conversations · Yapr Learn
In Japanese, strong certainty is usually expressed with adverbs placed before the verb, not by changing the verb form. The three most useful are kitto (きっと, 'surely, definitely'), kanarazu (必ず, 'certainly, without fail'), and tashika ni (確かに, 'certainly, indeed'). They contrast with tabun (たぶん, 'probably'), which marks possibility rather than confidence. This lesson teaches where these words go in a sentence, how they differ in strength and nuance, and how to use them naturally in everyday conversation.
By the end, you can…
- use kitto, kanarazu, and tashika ni to express strong certainty in Japanese.
- place certainty adverbs correctly before the verb and distinguish them from tabun.
Listen once. Try it slowly. Then say it without looking.
Checking available voices…
きっと来ます。
He's definitely coming.
Kitto kimasu.
Kitto expresses confident expectation; it is the closest everyday equivalent of 'definitely'. Here the subject is understood from context, so the sentence can mean 'He's definitely coming' or 'She's definitely coming.'
必ず行きます。
I will certainly go. / I will go without fail.
Kanarazu ikimasu.
Kanarazu is stronger and often implies a promise or obligation, like 'without fail'.
確かにそうです。
That is certainly so.
Tashika ni sou desu.
Tashika ni confirms something already stated or known, similar to 'indeed' or 'certainly'.
彼はきっと来るよ。
He's definitely coming.
Kare wa kitto kuru yo.
The sentence-ending particle yo adds friendly assurance in casual speech.
明日は必ず連絡します。
I will definitely contact you tomorrow.
Ashita wa kanarazu renraku shimasu.
Kanarazu with a polite verb form is common in promises and business settings.
Pronunciation guides are approximate. Slow playback keeps the original pitch.
Make it make sense
Useful pattern
Certainty adverbs normally come before the verb, and often after the topic marked by wa. Compare: 私はきっと行きます (Watashi wa kitto ikimasu, 'I'm definitely going') and 彼は必ず来ます (Kare wa kanarazu kimasu, 'He will certainly come'). With tabun (たぶん), the same position gives a weaker meaning: たぶん行きます (Tabun ikimasu, 'I'll probably go'). So the adverb, not the verb ending, carries the level of confidence.
When to use it
Use kitto for personal confidence or expectation, as in きっと大丈夫です (Kitto daijoubu desu, 'It'll definitely be fine'). Use kanarazu for promises, rules, and strong commitments, as in 必ず連絡してください (Kanarazu renraku shite kudasai, 'Please be sure to contact me'). Use tashika ni to agree or confirm: 確かに、その通りです (Tashika ni, sono toori desu, 'Certainly, that's right'). Avoid kanarazu for simple guesses about other people's feelings, where kitto sounds more natural.
Listen to each line, then take one part and reply out loud.
明日のパーティー、来ますか。
Are you coming to tomorrow's party?Ashita no paatii, kimasu ka.はい、きっと行きます。
Yes, I'm definitely going.Hai, kitto ikimasu.本当ですか。楽しみにしています。
Really? I'm looking forward to it.Hontou desu ka. Tanoshimi ni shite imasu.はい、必ず行きます。約束します。
Yes, I will certainly go. I promise.Hai, kanarazu ikimasu. Yakusoku shimasu.A little context goes a long way
Kanarazu can sound like a firm promise or even a mild obligation, so Japanese speakers often soften it with できるだけ (dekiru dake, 'as much as possible') when they cannot fully guarantee something. Kitto is warmer and more personal, while tashika ni is neutral and often used to acknowledge a point in discussion.
One thing to watch for
Using 必ず (kanarazu) for a casual guess, as in 彼は必ず来るでしょう for 'He'll probably come.'
Try this instead: For a guess, use きっと or たぶん instead: 彼はきっと来るでしょう (Kare wa kitto kuru deshou, 'He'll surely come') or 彼はたぶん来るでしょう (Kare wa tabun kuru deshou, 'He'll probably come'). Kanarazu implies a strong commitment or rule, not a casual prediction.
Your turn
Try answering out loud before checking a possible answer.
1How would you say 'I'm definitely going' using kitto?
Show a sample answer
きっと行きます。 (Kitto ikimasu.)
Kitto comes before the verb ikimasu and expresses confident expectation. 必ず行きます is also correct but stronger and more promise-like.
2Which word best fits a promise to contact someone tomorrow: kitto, kanarazu, or tabun?
Show a sample answer
必ず (kanarazu)
Kanarazu conveys 'without fail' and suits promises. Kitto is possible but less binding, and tabun would weaken the promise to 'probably'.
3What is the difference between 確かにそうです and たぶんそうです?
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確かにそうです means 'That is certainly so,' while たぶんそうです means 'That is probably so.'
Tashika ni confirms with confidence; tabun marks possibility. Both are grammatically fine, but they express different levels of certainty.
Place kitto, kanarazu, or tashika ni before the verb to show strong certainty; choose kanarazu for promises, kitto for personal confidence, and tashika ni for confirmation.
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