〜に決まっている: meaning and usage

How to form it

• verb (plain form)/い-adjective+に決まっている
• noun/な-adjective (stem)+に決まっている

How it is used

Says the speaker is sure something is so, leaving no room for doubt. Mostly spoken, often as 「〜に決まってる」. More colloquial, subjective and emphatic than 「〜に違いない」.

Examples

1. 肉を入れ忘れたカレーなんて、 不味いに決まっている！

   I forgot to add meat to the curry, it's going to taste awful!

2. 日曜日の遊園地は、混んでいるに決まってるよ。

   The amusement park on a Sunday is bound to be crowded.

3. 一人で全部やるなんて、無理に決まっている。

   Doing it all by yourself? That's obviously impossible.