なのだ

auxiliary

it is that ...; the thing is ...; I assure you that ...

Explanatory or assertive sentence-ending auxiliary. Used after nouns and na-adjectives to give a reason, explanation, or to add emphasis. Equivalent to のだ after verbs and i-adjectives.

See also: のだ

• 彼かれは学がく生せいなのだ。

  He is a student (you see).

• それが問もん題だいなんだ。

  That's the problem (I'm telling you).

auxiliary

did not ...

Only with reading なんだ

Kansai dialect negative past form, attaching to the -nai stem of a verb. Equivalent to standard ～なかった.

• 昨日きのうは行いかなんだ。

  I didn't go yesterday. (Kansai dialect)