YOU SAID:

hello sir, to my best knowledge, is this still available?

INTO JAPANESE

こんにちは、私の知る限り、これはまだ利用可能ですか？

BACK INTO ENGLISH

Hi, as far as I know, is this still available?

INTO JAPANESE

こんにちは、私が知る限り、これはまだ利用可能ですか？