YOU SAID:

You gotta be kidding me.

INTO JAPANESE

冗談でしょう。

BACK INTO ENGLISH

You must be joking.

INTO JAPANESE

冗談じゃないわ。

BACK INTO ENGLISH

I'm not kidding.

INTO JAPANESE

冗談じゃないよ。

BACK INTO ENGLISH

no kidding.

INTO JAPANESE

冗談じゃない。

BACK INTO ENGLISH

I am not joking.

INTO JAPANESE

冗談じゃない。

BACK INTO ENGLISH

I am not joking.