The Colombia international was heavily linked with both Juve and Premier League leaders Chelsea during the January transfer window.
A swap deal involving Mirko Vucinic was believed to have been put in place, only for Inter president Erick Thohir to pull the plug.
Inter supporters are delighted to still have Guarin at the San Siro and the 27-year-old believes it is fate which has kept him part of Walter Mazzarri's squad.
He told Inter's official website: "It was a sign of an important destiny. It was the second time that it happened.
"Even when I arrived at Inter, I had the opportunity to go to Turin and the fact that for a second time I am here, that is something important.
"What has happened has happened and is in the past. I have always been close to the fans, I feel the things that are done with their heart and I understand them.
"I always look at it as something positive - it's great to see the strength our fans give us, both when they do positively and indeed negatively, because it's always added motivation for me. Although, obviously, I'm never happy when they're not.
"There are lots of things I want to improve - the first is my consistency on the pitch so I can play a whole game at a higher tempo with the right focus."