The Portuguese full-back landed in Barcelona on Monday as a free agent following his departure from Al-Hilal, and is now awaiting the paperwork required to be registered in LaLiga.
Unlike his two previous spells at the club, both of which came on loan, this move ties him to Barcelona on a definitive basis.
"The difference is that in my first season I was left with a bittersweet feeling because I didn't win any titles, and I had that space in my heart to fill," Cancelo said.
"In the second spell I managed to do that. My love for Barça is the same and I'm very happy."
He also reflected on the difficult period before the move was finalised.
"The truth is it was two difficult weeks, but I had in my head what I wanted. What could have happened was that I stayed there for a year without playing. The goal was Barça. Thanks to my representatives and my family. If I hadn't come back, I would have stayed a year there without playing."
On the club's Champions League ambitions, Cancelo was unequivocal.
"A club like Barça has to be prepared to win everything. We're chasing this Champions League. We have a strong team that trains every day, where the experienced players help the younger ones. We're going to give everything to make that Champions League happen."
Asked about his role this season, the 32-year-old said he was ready to play anywhere across the back line.
"I'm here to help, whether it's on the right, the left or through the middle. I want to help achieve the objectives. We have a very good group, with players of great quality. I'm very happy, it's a childhood dream, this time for good."
Cancelo also had warm words for new teammate Rodri, who joined Barcelona from Manchester City this summer.
"He's, if not the best, one of the best players I've played with. He contributes a lot defensively and offensively. I have a very good relationship with him, it's easy to play with him. He's won a Ballon d'Or recently and decided to come here. He likes being here, and the club, and I think he identifies a lot with the way Barça play."
On his motivation to join Barcelona in the first place, Cancelo pointed to childhood heroes.
"Dani Alves is my only reference in my position. What I saw him do, I wanted to do too. Same with Ronaldinho. The Barça of 2009 was the best team in history, of what I saw. I always had that dream because of it."