Somebody claimed Satu is a Japanese name meaning "sugar". They're thinking of Satou. Not only is it spelled different, it's pronounced different (Satou = Sah-toh; Satu = Sah-too).
To those above, Satu can NEVER be a Japanese feminine name. It is true Sato means sugar, but when it is used for a first name, it doesn't mean that way, it means "a hometown" or "smart".