The Colombian rider was touted as a promising talent, and won Paris-Nice in 2014, but has lost his way at the French team, struggling to find form, motivation, and a decent racing weight. He preferred to spend long spells at home in Colombia rather than racing in Europe, putting him in conflict with the AG2R team management.
After being left out of the Tour de France, he reached a mutual agreement in August to leave the team, and he is confident that finally putting pen to paper with Movistar will allow him to put the unhappy days behind him and go on to fulfil his potential.
"I'm happy to belong to the number one team in the world, and I believe that with a person like Eusebio Unzué, who knows me and my characteristics very well, great things are on the way for me and for Movistar," the 26-year-old said in an interview with the Colombian Cycling Federation.
"I believe that being in a team like Movistar will consolidate me as a rider. I had some problems with AG2R and that made it hard to demonstrate what class of rider I am. But now with Movistar we are going to show the class of rider that I am."
Betancur would not expand on any underlying acrimony with AG2R but delivered a thinly-veiled snipe by saying that he considers the French outfit to be less professional than his new team.
"With AG2R all the experiences were good – I think they all give you life lessons," he said. "Now with Movistar the good things continue, but in a more professional manner and knowing how to do things. They know what type of rider I am, and I think they are much more professional in what they do. I think that now things are going to be much easier."
Betancur describes how the experienced Movistar boss Eusebio Unzué was a major factor in his decision to join the Spanish team - a decision that was easy to make. Hinting how unhappy he had become at AG2R, Betancur is now hopeful that the move is a turning point not just in his career but in his life as a whole.
"Eusebio is a person who I have great respect and admiration for, because he has had the team for many years, and he's had great riders, the best in the world. And now he has the best team in the world. He is a person from whom I have a lot to learn and so when the opportunity came to join Movistar I didn't think twice – I knew it was where I had to be.
"As a father, as a husband, as a son, things that happen are gifted by God and I believe that everything in my life is going to improve."