What is the required evidence for establishing a matter where the testimony of a single man is presented?

Primary text

If a man testifies regarding a matter where the testimony of a single woman is accepted, his testimony alone is accepted. This is because the man is considered more complete than the woman, so if she is accepted alone, he is more fittingly accepted alone. Furthermore, any matter where the statement of a single woman is accepted, the statement of a man is also accepted, as in narrations.