Compounds of んです

• んです
  (exp) the expectation is that ...
  the reason is that ...
  the fact is that ...
  it is that ...
• なんです
  (aux) it is assuredly that ...
  can say with confidence that ...
• もんですか
  (exp) (fem) used to create a rhetorical question indicating that the speaker actually believes the opposite is true
• そうなんです
  (int) (col) yes
  that is so
• そうなんですか
  (exp) is that so?
• どうかしたんですか
  (exp) is something up?
  is something wrong?
• いったい何なんですか
  (exp) what is it exactly?
  what is it precisely
• そうなんですけどねぇ
  (exp) that may be so