What language does bunsure mean?

"Bunsure" is not a word in any standard language. It's likely a misspelling or a made-up word.

Possible interpretations:

* A misspelling: It could be a misspelling of "be sure" or "bon sûr" (French for "of course").

* A made-up word: It could be a playful or humorous invention.

Without more context, it's impossible to know the intended meaning.