It was Donald J. Trump’s chance to sound contrite and mature, to explain away the sexually predatory boasts he was caught making on tape and to persuade Americans that — for all his no-apologies braggadocio — he was, in fact, capable of feeling shame.

Maura Cotter, 22, a senior at the University of Notre Dame, was shocked at what Mr. Trump did instead in Sunday’s debate: repeat, over and over, that what he had said on the 2005 recording, about forcing himself on women and grabbing their genitals, was simply “locker-room banter.”

It was, Ms. Cotter said, “not an apology — no reason to believe he’s changed at all.”

A classmate, Abigail Wilson, who is a registered Republican, listened closely to Mr. Trump and was reminded, she said, of the time she was groped by a stranger. The Republican nominee, she said soberly, “may not have physically harmed anyone with his words, but he has the power to do so by example.”