Various degrees of certainty

There are various vocabulary words that can express various degrees of certainty, some of which is listed below. But beyond memorizing additional vocabulary, we also need to learn a number of sentence endings that also indicate various degrees of certainty.

  1. 絶対 【ぜっ・たい】 – absolutely, without a doubt
  2. きっと – surely
  3. 多分 【た・ぶん】 – probably, perhaps, more likely than not

Indicating a fair amount of certainty

You will often hear 「でしょう」 at the very end of the sentence during, for instance, a weather forecast. It is used to express a fair amount of certainty when used with a flat intonation.


  1. 夜 【よる】 – evening
  2. 雨 【あめ】 – rain
  3. 降る 【ふ・る】(u-verb) – to precipitate
  4. 明日 【あした】 – tomorrow
  5. 晴れる 【は・れる】(ru-verb) – to be sunny
  1. 夜には、雨が降るでしょう
    At night, (it will) likely rain.
  2. 明日は、晴れるでしょう
    Tomorrow (will) likely be sunny.

In casual situations, when expressed with a rising intonation, it is used to seek agreement similar to 「ね」. However, while 「ね」 is used for what the speaker believes to be generally agreeable, 「でしょう」 can be more assertive and opinionated. 「だろう」 is another more masculine version of the casual usage of 「でしょう」.


  1. 間に合う 【ま・に・あ・う】(u-verb, exp) – to be in time for
  2. 言う 【い・う】(u-verb) – to say
  3. 時間 【じ・かん】 – time
  4. ある(u-verb) – to exist
  5. まだ – yet; still
  6. 大丈夫 【だい・じょう・ぶ】 – ok
  1. 間に合わないと言ったでしょう
    (I) said won’t make it in time, didn’t I?
  2. 時間があるから、まだ大丈夫だろう
    There’s time so (it’s) probably still ok.

Indicating a possibility

「かもしれない」 is another sentence ending that expresses a neutral possibility with about 50% level of confidence. It is simply the 「か」 and 「も」 particles combined with the potential negative form of 「知る」 (literally meaning “can’t know even if…”). This means that it conjugates just like any other negative ru-verb.


  1. 明日 【あした】 – tomorrow
  2. 遅い 【おそ・い】(i-adj) – late
  3. なる(u-verb) – to become
  4. 他 【ほか】 – other
  5. 店 【みせ】 – store
  6. 方 【ほう】 – direction
  7. 安い 【やす・い】(i-adj) – cheap
  1. 明日は遅くなるかもしれない
    Might be late tomorrow.
  2. 他の店の方が安いかもしれません
    Another store may be cheaper.

For casual situations, this grammar can be shortened to just 「かも」.

  1. ドア – door
  2. 鍵 【かぎ】 – key
  3. かける (ru-verb) – to hang; to lock
  4. 忘れる 【わす・れる】 (ru-verb) – to forget
  5. ケーキ – cake
  6. まだ – yet; still
  7. 残る 【のこ・る】 (u-verb) – to remain; to be left
  1. あっ、ドアに鍵をかけるのを忘れたかも
    Oh, (I) might have forgot to lock the door!
  2. ケーキはまだ残っているかもよ。
    There might be some cake left still, you know.

Expressing wonder/doubt

We can use 「でしょう」 or 「だろう」 with the question marker 「か」 to question whether something is actually true. This is often used to express doubt or reflection.


  1. これ – this
  2. いい (i-adj) – good
  3. 果たして 【は・たして】 – as was expected; really? (in questions)
  4. 謎 【なぞ】 – puzzle; riddle
  5. 解ける 【と・ける】 (ru-verb) – to be solved; to come untied
  6. 者 【もの】 – person
  7. いる (ru-verb) – to exist (animate)
  1. これでよかったのでしょうか
    Was it ok like this (I wonder)?
  2. 果たしてこのなぞを解ける者はいるんだろうか
    Will there be someone who can solve this riddle?

For casual situations, we can attach 「かな」 to the end of a sentence.


  1. 彼女 【かの・じょ】 – she; girlfriend
  2. どうして – why
  3. そんな – that sort of; that extent
  4. すぐ – soon
  5. キレる – to lose temper (slang from 【切れる】)
  1. これでよかったかな
    Was ok like this (I wonder)?
  2. 彼女はどうしてそんなにすぐキレるかな
    Why does she lose (her) temper that soon (I wonder)?

Recalling a memory

The sentence-ending particle 「っけ」 is used to describe something you’re trying to recall such as a vague memory or something you recently forgot.


  1. あれ – that (over there); huh?
  2. 鍵 【かぎ】 – key
  3. どこ – where
  4. 置く 【お・く】 (u-verb) – to put, to place
  5. 彼 【かれ】 – he; boyfriend
  6. 名前 【な・まえ】 – name
  7. 何 【なに/なん】 – what
  1. あれ?かぎをどこに置いたっけ
    Huh? Where did (I) place (the) key(s)?
  2. 彼の名前は何でしたっけ
    What was his name again?


  1. 料理 【りょう・り】 – cooking
  2. 下手 【へた】(na-adj) – unskilled, bad at
  3. ただいま – expression for coming back home (I’m home)
  4. お母さん 【お・かあ・さん】 – mother (polite)
  5. 買い物 【か・い・もの】 – shopping
  6. 出かける 【で・かける】(ru-verb) – to go out
  7. いつ – when
  8. 帰る 【かえ・る】 (u-verb) – to go home
  9. 来る 【く・る】 (exception) – to come
  10. たった今 【たった・いま】 – just now
  11. 家 【いえ】 – house
  12. 出る 【で・る】 (ru-verb) – to come out
  13. ~時 【~じ】 – counter for hours; ~ o’clock
  14. ぐらい – approximately, around
  15. そう – (things are) that way
  16. お腹 【お・なか】 – stomach
  17. 空く 【す・く】 (u-verb) – to become empty
  18. お父さん 【お・とう・さん】 – father (polite)
  19. 何か 【なに・か】 – something
  20. 作る 【つく・る】 (u-verb) – to make
  21. 簡単 【かん・たん】 (na-adj) – simple
  22. 物 【もの】 – object

Alice: I’m home. What about Mom?

Dad: (She) went out for shopping.

Alice: When is (she) coming back home?

Dad: (She) just left (the) house so (she’ll) probably come back home around 9:00.

Alice: Is that so? Ah, (I’m) hungry!

Dad: Then shall dad make something?

Alice: Dad, (you’re) bad at cooking, right?

Dad: (I) might be able to make something simple, you know?

Alice: Is that so (you think)?

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