に決まっている

Bound to Be

Level 3Sounds Like nikimatteiru

Use に決まっている when you are absolutely certain about something based on your own intuition, values, or common sense. It translates to 'bound to be,' 'definitely,' or 'of course it is.'

How It Works

に決まっている (or the casual に決まってる) is a powerful way to state that there is no doubt in your mind about a situation.

1. Subjective vs. Objective:
While other patterns like に違いない rely on logical evidence, に決まっている is often used for personal biases or things the speaker considers 'common sense.' For example, 'If it's a movie by this director, it's bound to be good!'

2. Register and Contractions:
This is primarily a casual, spoken expression. In very casual speech, you will often hear the contraction に決まってんだ. Even when used in the polite form (〜に決まっています), the assertive nuance remains, so use caution in formal settings.

3. Common Pairings:
To add even more emphasis, this pattern is frequently paired with adverbs like 絶対 (definitely) or どうせ (anyway/in any case).

4. Formation:
It attaches directly to the plain form of verbs and adjectives. Crucially, for な-adjectives and nouns, you must drop the だ before adding に決まっている.

Examples (5)

  1. そんなの、嘘に決まっているよ！

    That's bound to be a lie!

    Word by Word: That kind of thing, lie (particle) decided is (particle)!

    Here, the speaker is expressing immediate and strong disbelief, asserting that the information is obviously false.

  2. 一生懸命練習したんだから、今度の試合は勝つに決まっている。

    We practiced so hard, we're bound to win the next match.

    Word by Word: With all one's might practiced because, this time's match win (particle) decided is.

    The speaker uses their own effort as the basis for a strong conviction that victory is certain.

  3. あんなに高い料理なら、美味しいに決まっている。

    If the food is that expensive, it's obviously going to be delicious.

    Word by Word: That much expensive cooking if, delicious (particle) decided is.

    This shows a subjective judgment: the speaker assumes high price naturally equals high quality.

  4. 一人でそんなにたくさん食べられるわけない。残すに決まってるよ。

    There's no way you can eat that much alone. You're definitely going to leave some.

    Word by Word: One person by that much a lot can eat reason not. Leave (particle) decided is (particle).

    Uses the contracted casual form 「〜に決まってる」 to express a strong prediction about the outcome.

  5. 絶対無理に決まってんだろ！

    It's obviously impossible, right?!

    Word by Word: Absolutely impossible (particle) decided is (particle) (particle)!

    This example uses the emphatic adverb 「絶対」 and the very casual contraction 「〜に決まってんだ」.

Common Mistakes

  • Keeping the 「だ」 copula with nouns or na-adjectives.

    彼は犯人だに決まっている。
    彼は犯人に決まっている。

    When attaching to a noun or a な-adjective, you must not include 「だ」. It attaches directly to the word stem.

  • Using it in formal situations with superiors.

    社長、それは無理に決まっています。
    社長、それは難しいのではないでしょうか。

    Because this pattern sounds very assertive and dismissive of other possibilities, telling a boss 'it's obviously impossible' can come across as rude or argumentative.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

に決まっているLevel 3Bound to Be

Learn This First

に決まっている is an idiomatic expression meaning 'it is bound to be' or 'it is definitely the case.' It is formed by the particle に and the resultative form of the verb 決まる (to be decided). To understand it, learners need to be familiar with the ~ている form for states and how the particle に marks a resulting state.

Words in This Pattern

に決まっている決まる