Mr. Trump’s aides have been eager for his wife to make a public show of support for him, especially after the “Access Hollywood” recording dominated several media cycles and drove some Republican elected officials to abandon his candidacy.

A week ago, Mr. Trump’s adult children, along with aides to his campaign, urged Ms. Trump to agree to a sit-down interview with her husband, an echo of the “60 Minutes” interview that Bill and Hillary Clinton did in 1992 after sexual infidelity allegations arose against Mr. Clinton. That appearance helped stabilize Mr. Clinton’s presidential campaign.

But Ms. Trump had little interest in it, and the idea died.

Ms. Trump has never enjoyed the political stage, and was stung by media coverage in July, when it was revealed that her anticipated Republican National Convention speech borrowed lines from Michelle Obama’s 2008 address to the Democratic National Convention. She has been absent from the campaign trail since, save for brief appearances at the first two general election debates, and has been spending time with the couple’s young son, Barron.

She put out a written statement of support for her husband after the tape surfaced. But with Mr. Trump’s favorability among women perilously low, his advisers wanted Ms. Trump to do more.

Seated in the family’s penthouse atop Trump Tower, Ms. Trump seemed occasionally ill at ease but determined to convey several points: that her husband is a gentleman, that the media is out to get him and that she is staying strong despite the ugliness. She showed an ability to remain on message that her husband sometimes lacks.

“I watched TV hour after hour bashing him,” Ms. Trump said of the television coverage the weekend the 11-year-old recording was first revealed.