私としては、多数決で決めることに賛成です。 in this sentence why did we use に particle before 賛成です.
is 賛成 here working as a noun or adjective ?
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2019-07-17T10:30:59.857
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2019-07-17T22:47:50.353
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grammar particles particle-に
決めることに賛成です Ni particle
This 賛成 is a noun known as a [_no-
adjective_](https://japanese.stackexchange.com/q/2770/5010). A no-adjective is
a noun that translates to an English adjective. Unlike ordinary nouns, no-
adjectives and na-adjectives can be modified by adverbs (e.g., やや, かなり, とても)
and adverbial expressions, which includes ～に.

Similar examples:

  * この曲は若者に人気です。  
This song is popular among young people.

  * 若者に人気の曲  
a song that is popular among young people

  * この風習は日本に特有です。  
This custom is unique to Japan.

  * これは日本に特有の風習です。  
This is a custom that is unique to Japan.

賛成 also works as a plain (suru-)verb:

  * 多数決で決めることに賛成します。
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2019-07-17T14:35:05.523
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answer
Adding on to naruto's post, think about the meaning of 賛成: _"agreement"_. As a
noun, it can be used in the sense of _"agreement to / with something"_. As a
verb with する, it becomes _"to agree to / with something"_. Much like the how
the English terms _"agreement"_ and _"agree"_ are used, where one _agrees_ or
_is in agreement **to** or **with** something_, the Japanese requires a **に**
to mark the "something" that serves as the indirect object of this verbal noun
or verb construction.

Let's look again at your sample sentence.

> 私【わたし】としては、多【た】数【すう】決【けつ】で決【き】めること​ **[に]【●】 ​賛【さん】成【せい】です**。

Here's one possible translation.

> As for me, I **am in agreement** **[with]{●●●●}** deciding by majority vote.

Note the parallel between the **に** in Japanese and the **with** in the
English. More natural phrasing in English might say something like,

> For my part, I **agree [that]{●●●●}** we should decide by majority vote

... in which case the **に** would align with the **that**.
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2019-07-17T19:02:28.157
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