YOU SAID:
if it happens it doesnt happen but if it doesnt happen it might happen
INTO JAPANESE
それが起こった場合、それは起こらないが、それが起こらなければ、それは起こるかもしれない
BACK INTO ENGLISH
If it happens, it won't happen, but if it doesn't happen, it might happen
INTO JAPANESE
それが起こった場合、それは起こらないだろうが、それが起こらなければ、それは起こるかもしれない
BACK INTO ENGLISH
It wouldn't happen if it happened, but if it doesn't happen, it might happen
INTO JAPANESE
それが起こった場合、それは起こらないだろうが、それが起こらなければ、それは起こるかもしれない
BACK INTO ENGLISH
It wouldn't happen if it happened, but if it doesn't happen, it might happen
You've done this before, haven't you.