YOU SAID:
basil is my best friend
INTO JAPANESE
バジルは私の親友
BACK INTO ENGLISH
Basil is my best friend.
INTO JAPANESE
バジルは、私の親友です。
BACK INTO ENGLISH
Basil is a good friend of mine.
INTO JAPANESE
バジルは、私の良き友人です。
BACK INTO ENGLISH
Basil is a good friend of mine.
That didn't even make that much sense in English.