YOU SAID:

I was flummoxed whilst trying to understand him

INTO JAPANESE

私は彼を理解しようとしながら面食らった

BACK INTO ENGLISH

While I was trying to figure out his flummoxed

INTO JAPANESE

一方、彼の面食らったを把握しようとしていた

BACK INTO ENGLISH

On the other hand, flummoxed his had been trying to figure out

INTO JAPANESE

その一方で、面食らった彼は把握しようとしていた

BACK INTO ENGLISH

On the other hand, had him flummoxed trying to figure out

INTO JAPANESE

その一方で、彼の面食らったにいた把握しよう

BACK INTO ENGLISH

Knocked his face on the other hand, to had trying to figure

INTO JAPANESE

その一方で、理解しようと試みていた彼の顔をノック

BACK INTO ENGLISH

On the other hand, was trying to understand his face knock

INTO JAPANESE

一方では彼の顔のノックを理解しよう

BACK INTO ENGLISH

On the other hand trying to figure out his face knock

INTO JAPANESE

その一方で彼の顔のノックを把握しよう

BACK INTO ENGLISH

On the other hand trying to figure out his face knock