YOU SAID:

Hello little sister, how are you doing.

INTO JAPANESE

こんにちは妹、お元気ですか。

BACK INTO ENGLISH

Hello sister, how are you.

INTO JAPANESE

こんにちは姉妹、お元気ですか。

BACK INTO ENGLISH

Hello Sister, how are you.

INTO JAPANESE

こんにちはシスター、お元気ですか。

BACK INTO ENGLISH

Hello Sister, how are you.