:) The sentence above is clearly out of context, or what we call "Incomplete sentence". the reason for ambiguity is the name "Rosa", which cannot be indefinite, so one cannot tell if "His neighbor (the) Rosa" or "His neighbor Rosa"... To simplify, if the sentence was "His neighbor is a woman", versus "His neighbor, the woman, is..." the second is obviously incomplete. But we know that in Arabic by the definite article (there is no "is") :
جارته امرأة: His neighbor is a woman
جارته المرأة... His neighbor, the woman, is...