我不是在開玩笑。

I'm not joking.

Source: Tatoeba

Sentence Composition

1 我 wǒ
  1. I
  2. me
  3. my
=2 不是 bùshì
  1. no
  2. is not
  3. not
=2 不是 bùshi fault; blame
3 在 zài
  1. to exist; to be alive
  2. (of sb or sth) to be (located) at
  3. (used before a verb to indicate an action in progress)
4 開玩笑 kāiwánxiào to play a joke; to make fun of; to joke