〜に決まっている
JLPT N3:definitely / of course
Says something is obviously true: "definitely", "of course", "bound to". It is conversational, and because it allows no doubt it can sound pushy.
How to form it
- Put the plain form before に決まっている: 勝つに決まっている (they're bound to win).
- Nouns and な-adjectives take it directly, with no だ: 嘘に決まっている (it's obviously a lie).
Examples
そんなの、嘘に決まっている。
That's obviously a lie.
こんな時間に電話したら、迷惑に決まっている。
Calling at this hour is bound to be a nuisance.
Similar meaning
- 〜に違いないmust be
"Must be": a reasoned conviction; more formal.