How to parse わかってるって 例のニセモノがやったに決まってんだ

Question

Shoudn't there be a nominalizer after やった? I think it's just a casual contracion, but have not seen it before. Moreover, I have seen 決まっているだろう, or contracted to 決まってんだろう before, but in this particular example there's just だ, and that I do not understand. At last, the って in わかってるって serves just to sort of emphasize it?

Answer 1

First, 決まってんだ is a contraction of 決まってるんだ (which in turn is a contraction of 決まっているのだ). See this answer.

Next, you don't need a nominalizer (の) before に決まっている even in formal writings. It's not incorrect to put の, but it's much less common in reality. に can safely take the 終止形 (dictionary) form of a verb in several types of contexts:

• ～するに決まっている, ～するに違いない, ～するに相違ない
• ～するには (meaning "in order to")
• 言うに(は), 見るに, 思うに, etc. (What does the に do in 表情から察するに?)
• ～するにしては (meaning "for", "considering")
• ～するにしろ, ～するにせよ, ～するにしても, ～するにしたって (meaning "even if")
• ～するにつけ (meaning "whenever")
• ～するに留まる

Basically you have to memorize these patterns as-is. I think the following questions are related to the reason why に can sometimes take a "bare" verb/adjective:

• How can （の）目指すは be grammatical?
• Zero-nominalisation - Why and When?

(By the way, this reminded me of this question in English Language Stack Exchange.)