YOU SAID:

I happen not to be not very not happy.

INTO JAPANESE

私はたまたま幸せではないのではありません。

BACK INTO ENGLISH

It happens not to be happy.

INTO JAPANESE

幸せではないことが起こります。

BACK INTO ENGLISH

What happens is not happening.

INTO JAPANESE

起こることは起きていません。

BACK INTO ENGLISH

It does not happen.

INTO JAPANESE

起こりません。

BACK INTO ENGLISH

It will not happen.

INTO JAPANESE

起こりません。

BACK INTO ENGLISH

It will not happen.