。
She replied that she had never met that man before.
Literal
She [topic-は] that man [recipient-に] before met [past-experience-こと-が] not-exist [quotative-と] replied.
答える ('to answer, reply') frames this as a response to something — perhaps a question in court, an interview, or an investigation. The pattern ~に会ったことがある ('have met X before') is the canonical 'past experience' construction; negated with ない, it asserts that the experience never happened in the speaker's life. 男の人 is gentler and more neutral than bare 男, slightly softening the reference and feeling more polite when describing a stranger.