House Speaker Paul Ryan said his former 2012 presidential running mate Mitt Romney remains a "good friend," and he would love to see the ex-Massachusetts governor be nominated as secretary of State, but he doesn't know yet what President-elect Donald Trump will eventually decide.

"I think he's going to make his choice pretty soon," the Wisconsin Republican told CNBC's "Squawk Box" on Wednesday about Trump's decision. "I think Mitt would be fantastic. He's one of the most competent people I've ever known."

Ryan deferred comment about Romney's sharp criticism of Trump during the 2016 presidential campaign to Romney himself, but admitted he and his former running mate were both surprised to find Trump was considering him for the vital Cabinet post.

However, Ryan said he is not surprised Trump has forgiven Romney for his comments, including in March, when he called the then-candidate a "phony."

"Now that I've gotten to know Donald Trump, which I didn't before, I'm not surprised," Ryan said. "He's extremely magnanimous in this . . . he is a very forgiving, very magnanimous kind of guy. I'm actually very impressed with how he's handled this.

"I'm very impressed with how he's handled just former critics from his own party, like say Mitt Romney, to everybody else. That he's basically saying let's unify this party, unify this country, get things done. That's exactly what I think people want to see."

Also, Ryan discussed Trump's lack of political experience, saying Wednesday he has "every confidence" Trump will separate himself from his business interests while serving in the White House.

"I have every bit of confidence he's going to get himself right with moving himself from the business guy that he is to the president he's going to be," Ryan told the program.

Trump plans next week to offer details about how he will separate from his businesses, indicating his three oldest children, Ivanka, Donald Jr., and Eric will run his business operations.

The new president-elect maintains several businesses and real estate holdings, and has already sold off his stock in other businesses in order to avoid the appearance of having a conflict of interest in his decisions.

Ryan said Trump's "legal details" for the business separation "do not concern him in Congress."

Meanwhile, Ryan said he is more concerned with pushing through an aggressive Republican policy agenda this year, and said lawmakers have been working on tax reform legislation for over a year.

"We've been working on welfare legislation, healthcare legislation, regulatory agenda, energy policy, so it's not just talking points," Ryan said. "What I told our members, assume we get the White House and Congress, do everything you need to do to get ready."

But that does not mean planned reforms on Obamacare will happen immediately – they will take time over a transition period.

"I think people believe with all the rhetoric, 'My gosh, in February I'm going to lose what I've got right now and I'll have nothing to go to," Ryan said. "The point we're trying to make is this law is just failing very, very quickly. We've got to replace this law. And we will have a transition period so that we don't pull the rug out from under people."

Congress will also move on regulatory reform, Ryan said, and on other items such as securing the nation's borders, tax reform, and more.

"We've got a big bold agenda we're working on," Ryan said. "We campaigned on this. We wanted to tell the country very clearly, here is what we hope to do under a unified Republican government if we win the election, which we just did. We feel we have the obligation to follow up on that and make good on those promises."