[Unknown Zambian Dialect > English] Name of a Dog

Several years ago I knew a person with a dog whose name was pronounced **ah-sweet-uh** (could be mistaken on pronunciation). This person had spent time in Zambia with the Peace Corps, and told me the name meant *best friend*, but I forget the language they were speaking.

I would really like to know if I'm remembering the word correctly, and the correct spelling/pronunciation.