Tia, 27, dated Colton briefly in early 2018 before he competed for Becca Kufrin's heart on The Bachelorette's fourteenth season.
The pair then reunited and gave their romance a second chance on Bachelor in Paradise's fifth season last summer, however, Colton decided to end things during the show and left Tia brokenhearted.
Tia insisted to ET she hasn't been watching Colton's season unfold on television but she's been keeping up with the highlights on Twitter.
"He makes out a lot. They don't talk a lot on dates, they just make out a lot," Tia joked. "[But] I think it's going to end well, I really do."
Tia predicted the 26-year-old charity founder and former professional football player will choose someone "blonde" and in her "early twenties" at the end of The Bachelor's 23rd season, although Colton has remained "pretty tight-lipped" about the events that transpired towards the end of his journey.
"I do [think he'll end up with someone]," Tia said. "I don't think he'd do this whole thing if he wasn't serious about it."
Tia revealed she currently has an amicable relationship with Colton despite their past. In fact, she said Colton touched base with her after he wrapped taping The Bachelor late last year.
"He actually called me after filming and said, 'I wanted to be honest and genuine throughout. I quit at one point, tried to quit, came back.' He felt like it was wrong and would be a disservice to the girls. So that's why I think he's serious about this and he really did it to find a wife," Tia told ET.
If Colton's The Bachelor season ends happily, he and Tia both will both be in successful relationships after their time on Bachelor in Paradise.
FOLLOW REALITY TV WORLD ON THE ALL-NEW GOOGLE NEWS!
Reality TV World is now available on the all-new Google News app and website. Click here to visit our Google News page, and then click FOLLOW to add us as a news source!
Tia is currently dating a new man, Cory Cooper, and she's pretty smitten with him.
"[Colton] wants to meet Cory, but Cory's like, 'Eh, that's your ex, that's kind of strange,'" Tia admitted, adding however that Cory has been very supportive of her.
"I did not watch her on TV or know who she was," Cory told ET.
"I was actually set up through a coworker of mine, and we just get along. We're from the country and we just really bond... We're long distance, so when we're together, it's really good."
Colton's The Bachelor season is heading into its seventh episode, and only seven women remain in the running for his heart.