YOU SAID:

I solemnly swear that I'm up to no good.

INTO JAPANESE

私はよからぬことを誓います.

BACK INTO ENGLISH

i solemnly swear.

INTO JAPANESE

私は厳粛に誓います.

BACK INTO ENGLISH

i do solemnly swear.

INTO JAPANESE

厳粛に誓います.

BACK INTO ENGLISH

i do solemnly swear.