YOU SAID:
Bertil think he is a dwarf
INTO JAPANESE
Bertilは彼が小人だと思います
BACK INTO ENGLISH
Bertil thinks he is a dwarf
INTO JAPANESE
Bertilは彼が矮星だと思っている
BACK INTO ENGLISH
Bertil thinks he is a comet
INTO JAPANESE
Bertilは彼が彗星だと思っている
BACK INTO ENGLISH
Bertil thinks he is a comet
That didn't even make that much sense in English.