Expressing Uncertainty in Japanese

How to Express Uncertainty

When speaking Japanese, you won't always be completely sure about what you are saying. Whether making a guess, stating an opinion, or politely softening a statement, expressing uncertainty is a core part of the language.

Depending on how confident you are in your guess, Japanese offers several different words and grammar patterns. We will look at the most common ones: , , , and .

たぶん (Tabun)

The simplest way to add uncertainty to a sentence is by using the adverb , which translates to "probably" or "maybe." Because it is an adverb, you can just place it at or near the beginning of your sentence without needing to change any verb conjugations or grammar structures.

〜かもしれない (Kamoshirenai)

If you are tossing up a 50/50 guess, you can attach to the end of a sentence. It translates directly to "might" or "may."

It is attached directly to the plain form of verbs and i-adjectives. For na-adjectives and nouns, you simply attach it directly to the word without adding .

Note: In casual speech, this is frequently shortened to just .

〜だろう / 〜でしょう (Darou / Deshou)

When you are fairly confident in your guess (around 80% certainty), you use (casual) or (polite). It translates to "probably" or "I expect that..."

Like kamoshirenai, it attaches directly to the plain form of verbs and i-adjectives, and directly to nouns and na-adjectives (again, dropping the ). It is also very common to pair these patterns with to emphasize the guess.

〜と思う (To omou)

Another way to express uncertainty is to frame your statement as an opinion or personal thought. You can do this by using the verb combined with the quoting particle . (If you need a refresher on particles, check out the Introduction to Japanese Particles post).

Simply take a plain form sentence and add to the end. Unlike the previous patterns, if a sentence ends in a noun or a na-adjective, you must include before the quoting particle.

Study Tips

While it can be helpful initially to think of these expressions in terms of "percentages of certainty" (like 50% for kamoshirenai and 80% for darou), real conversations rarely map perfectly to these numbers.

Instead of trying to memorize exactly when to use which phrase, focus on recognizing them when you read or listen. Over time, through consistent A Practical Guide to Language Immersion, you will develop a natural intuition for the subtle differences in confidence and politeness they convey. You do not need to drill these rules perfectly; simply knowing they exist is a great starting point.