Former New York City Mayor Rudy Giuliani weighed in on "Hannity" tonight about what he thinks Hillary Clinton's biggest problem is. 

Clinton, who announced on Sunday that she's running for president in 2016, is currently in Iowa campaigning. 

Giuliani said part of Clinton's problem is trustworthiness.

"If she’s going to present herself, she has to present herself as an authentic person to overcome the untrustworthiness that has built up over the years with regard to all of the different things," he told Hannity.

"This seems like a woman that maybe this campaigning thing isn't cut out for her," Giuliani added.

Watch the full video above to hear why the former mayor believes Sen. Marco Rubio (R-FL) had the "perfect" rollout announcement of his candidacy for president.

You Might Also Like...

Giuliani: I Don't Want to See Nuclear Button Put in Hands of a Maniac

12-Year-Old Conservative Superstar Defends Giuliani, Blasts Obama

'I'm Right About This': Giuliani Doubles Down on Obama Remarks

'He's More of a Critic': Giuliani Says Obama Doesn't 'Love America'