Real must overturn a 2-1 deficit on Friday in Manchester to reach the quarterfinals.
"We want to win everything possible and gain more confidence that way.
"We haven't had games to play beforehand, so we have time to prepare ourselves.
"The best team on the day will win.
"We'll go into [the game] with hunger to win and the necessary determination."
While Varane is feeling confident ahead of the match, he knows it will be a tough evening in Manchester.
"[It will be] a difficult game against a very good team," he added.
"The first leg was a top quality game, with pressing from both teams.
"It was decided by the small details.
"[Real Madrid and City are] two teams that like to have the ball, are very intense and that require lots of concentration.
"These are the best games in the Champions League - the ones that are decided by very little.
"They are why we love this competition."