YOU SAID:

I know he's been a good friend of mine But lately something's changed that ain't hard to define

INTO JAPANESE

私は彼が私の親友であったことを私は知っています

BACK INTO ENGLISH

I know that he was my best friend

INTO JAPANESE

私は彼が私の親友であることを知っています

BACK INTO ENGLISH

I know that he is my best friend

INTO JAPANESE

私は彼が私の親友であることを知っています

BACK INTO ENGLISH

I know that he is my best friend