"Look, I have hope. I have hope!" Booker said. "This is something really special. She's challenged me in ways that I needed to be challenged."
Booker promised host Wendy Williams he will buy a tasteful engagement ring for Dawson, should he propose.
"She is this righteous activist," he said of Dawson. "She has a fashion line in Africa about empowering women, so whatever I get will be conscious and reflect the values of a couple, should I decide to do this."
Booker and Dawson first met at a fundraiser for politician Ben Jealous. Booker recalled how he met Dawson again at a roof party hosted by actress and comedian Sarah Silverman.
"The roof was on fire that night," Booker said.
"I have a lot of confidence in a lot of areas, but I tell you, I did not feel confidence when I asked for her phone number," he added. "I have a lot of confidence when it comes to justice and opportunities, but this was a shy moment for me, definitely. But, she was merciful."
Booker and Dawson were first linked in January. The couple got close at the Los Angeles premiere of Dawson's movie Zombieland: Double Tap in October.
Booker praised Dawson in an interview with NBC10 Boston less than two weeks after the premiere.
"She is an extraordinary woman who has transformed my life, and you know, it's just weird to be running for president at a time that I'm the happiest I've ever been in my persona life, as well," he said. "So I'm excited to win the presidency and perhaps have one of the more extraordinary significant others that has ever been with a president."
Booker will appear Wednesday at the Democratic primary debate in Atlanta, Ga.