YOU SAID:

This is a test, which will probably fail spectacularly.

INTO JAPANESE

これはおそらく見事失敗のテストです。

BACK INTO ENGLISH

This is probably fine is a failed test.

INTO JAPANESE

これはテストです。

BACK INTO ENGLISH

THIS IS A TEST

INTO JAPANESE

これはテストです。

BACK INTO ENGLISH

THIS IS A TEST