America is now a country without hope, Michelle Obama has said. Asked by Oprah Winfrey if her husband’s administration had lived up to its promise of hope, the first lady said yes, adding: “Because we feel the difference now. Now we’re feeling what not having hope feels like. Hope is necessary.”

She added: “And Barack didn’t talk about hope because he thought it was a nice slogan to get votes. He and I and so many believe ‘what else do you have if you don’t have hope? What do you give your kids if you can’t give them hope?’” In what is likely to be Obama’s last interview of the year, she suggested that Americans would miss “having a grown-up in the White House”, drawing a clear contrast between her husband and the man who will replace him on 20 January, Donald Trump.

And she compared the nation to a toddler who falls over and looks to their parent to know if they should cry or not.

“I feel that Barack has been that for the nation in ways that people will come to appreciate,” she said. “Having a grown-up in the White House who can say to you in times of crisis and turmoil ‘hey it’s going to be OK, let’s remember the good things that we have, let’s look at the future, let’s look at all the things that we’re building’.”

On Thursday, the first lady played that role herself to a group of students, many of them young black women, who had gathered at the White House for a screening of the film Hidden Figures, which documents the role of black female mathematicians in the space race.

“Look at this eight years,” she said. “We were supposed to be hidden. People didn’t even want to believe we were real. But here we are, eight years later. “But it’s up to all of you, our young people, to continue that legacy. It’s your turn now. All right?” she said.

In that interview she also gave a message about diversity and inclusiveness that could be read as a criticism of Trump.

At a time when the Republican president-elect is drawing up a cabinet dominated by older white men, the first lady said: “As we move forward in life and we get access to these seats of power, these tables of power, I want you to look around and make sure there’s diversity at the table.

“Because you don’t come up with the right answer if everyone at the table looks the same and thinks the same and has the same experience – you never come up with the best answer. So when you get these seats at these tables of power, your obligation is to make sure the conversation is diverse.”

She added: “Because what we saw in this film is that when we pull together men and women, people of every background and colour and faith, immigrants who’ve come here from across the globe to make America their home – when we bring all of that brainpower to the table, anything is possible, even going to the moon, right?”

President-elect Trump was endorsed by the Ku Klux Klan and accused of tapping into crude white nationalism while insulting Mexicans and Muslims. Michelle Obama was arguably one Trump’s most eloquent and powerful adversaries during the campaign, denouncing his treatment of women after allegations of sexual harassment came to light.

She told the students that if they take anything from the past eight years, “I want you to see that it does not matter what you look like, it doesn’t matter how much money your parents have – none of that matters. Skin colour, gender is the most ridiculous defining trait that we cling to. It doesn’t matter.”

The Oprah Winfrey interview with the first lady airs Monday night on CBS at 8pm ET.