YOU SAID:

One must reasonably assume there to be a fish under his doorstep

INTO JAPANESE

戸口の下に魚がいると合理的に想定しなければならない

BACK INTO ENGLISH

We must reasonably assume that there is a fish under the doorway

INTO JAPANESE

戸口の下に魚がいると合理的に仮定する必要があります

BACK INTO ENGLISH

We must reasonably assume that there is a fish under the doorway