Ferguson, having led United to the 13th Premier League title of his reign in 2012-13, assured the French defender he would remain in charge at Old Trafford.
And the Scot was apparently confident of bringing Portuguese superstar Ronaldo back to the club from Real Madrid, having sold the prized asset to the Liga giants for £80 million in 2009.
None of that came to pass, though, with Ferguson announcing his retirement on May 8 2013.
"I remember we talked maybe two weeks before and he said, 'Patrice, I will be here another five years'," he said.
"I said, 'Yes boss. Let's do it.' I was so convinced. He was looking younger and younger, amazing. He even told me '99 per cent, Cristiano Ronaldo will come'. I was like, 'wow, we are ready to bounce back and to even win the Champions League again.
"After that everyone knows what happened. You know when you are lost and you feel like the world is crumbling? It was a big trauma, I felt lost."
Evra reached the Champions League final with Juve last season, while United, having failed to qualify for the tournament under Moyes, returned to Europe's elite club competition after finishing fourth in Louis van Gaal's first campaign in charge last term.