Use of んじゃないんだ in this sentence

Question

何で高校の制服。。?

Why I got to wear a high school uniform?

最高に似合ってる

It fits you the best!

And the answer is

感想を求めたんじゃないんだよな

What is the purpose of んじゃないんだin this sentence? I guess he saying he didn't ask for the other impressions?

Answer 1

In this sentence, there are two explanatory-の used in a row. The first one is used with ない. A very literal translation would be "It's that it's not that I asked for your impression".

• 感想を求めたんじゃないんだよな
  感想を求めたのではないのだ(よな)

The first の(ではない) indicates 感想を求めた is a reason/explanation for the previous context, so it's somewhat like "(not) because I wanted your 感想". From Tofugu: んだ・んです:

Adding an explanatory tone is one of the most common features of んだ.

And the second の(だ) is used to convince the listener or resolve a misunderstanding. An English equivalent might be "Hey", "Come on", "I tell you" or something. From the same article:

んだ can be used to fill in the gap of understanding between you and your listener not only when your listener is missing some information, but also when they’re misunderstanding something.

So to put the original sentence very verbosely, 感想を求めたんじゃないんだよな is like "Hey you're misunderstanding, (the reason I said "何で高校の制服?") is not because I wanted your impression!" Of course something like "I didn't asked it!" is usually enough as an English translation.