Meaning
に決まっている is used when the speaker has strong confidence and conviction about a prediction or expectation. It conveys the meaning 'it must be...' or 'it's definitely going to be...' The speaker is asserting their confident belief about something. It can be used with verbs, i-adjectives, na-adjectives, and nouns.
Formation
| Part of speech | Formation |
|---|---|
| 動詞普通形 | に決まっている |
| い形容詞 | に決まっている |
| な形容詞 | に決まっている |
| 名詞 | に決まっている |
Examples
-
売れるに決まっている
It's bound to sell well -
雨が降るに決まっている
It will definitely rain -
彼はビジネスセンスがあるので、資金さえあれば、成功するに決まっている。
Since he has good business sense, if he just has the funds, he's sure to succeed -
あのお好み焼きの店は毎日沢山の人が並んでいるのだから、おいしいに決まっている。
That okonomiyaki restaurant has long lines every day, so it must be delicious -
勝手にあの歌手の曲を音組で使ったら、著作権の侵害になるに決まっているだろう。
If you use that singer's song in a program without permission, it's definitely going to be copyright infringement
Summary
- Used to express the speaker's strong conviction and certainty about a prediction or outcome
- に違いない has the same meaning but に決まっている is more casual/colloquial while に違いない is more formal
- Can attach to verb plain form, i-adjectives, na-adjectives, and nouns to indicate definite expectation