The Ugly Betty actress plays Quinn, a conniving stripper who has struck up a romance with Neil Patrick Harris's alter ego and moves in with him on the show's March 19 episode.
Newton told TV Guide: "They're both on the same page, which is why it's working out so well for them.
"I think that even Barney and Quinn are surprised by this development, but they feel pretty confident and really happy together, so why not give it a shot?
"Underneath [Quinn's] conniving exterior, Barney has gotten to her heart and she has done the same to Barney. They both have a sense of adventure and a sense of fun. They're a perfect match."
Asked whether Quinn could be Barney's mystery bride, Newton teased: "I think she's a very good contender. They have not told me anything.
"But if I got to wear a wedding dress and marry Neil Patrick Harris - I mean, I would die... I would totally come back if they want me to. I would love to see Quinn and Barney going strong."
Newton has also been cast in new Fox comedy pilot The Goodwin Games, developed by How I Met Your Mother creators Carter Bays and Craig Thomas.
How I Met Your Mother airs Mondays at 8/7c on CBS.