is a construction with several different forms, each meaning roughly the same thing. This expression behaves similarly to だ
by themselves (asserting that something is true). However, the addition of の strengthens the relationship being highlighted. Due to this, it will come across a bit like ‘it is a fact that (A)’ in English.
In these sentences, we can think of the ん
, or の
as simply adding emphasis to the statement. Due to の
adding emphasis, this expression will be heard very frequently in explanations.
There is no real difference between ん and の. Only の is considered ‘correct Japanese’, but ん evolved to make things easier to say. ん is the most common form in spoken Japanese, and the use of の could be considered a bit formal, or ‘stiff’.
While both the だ
forms are equally as natural, only the です
form will be used if adding か
to the end ～んですか
. This construction shows that the speaker is looking for an explanation about something.