YOU SAID:

i promised my self not fail yet i fail

INTO JAPANESE

私は自分自身が失敗しないことを約束しました

BACK INTO ENGLISH

I promised myself not to fail

INTO JAPANESE

失敗しないと約束した

BACK INTO ENGLISH

Promised not to fail

INTO JAPANESE

失敗しないことを約束

BACK INTO ENGLISH

Promise not to fail

INTO JAPANESE

失敗しないことを約束

BACK INTO ENGLISH

Promise not to fail