Darmian appears set to move to United just after Torino accepted an initial fee of around ￡13million.
Ventura told Sky Italia: “We have worked with each other for some time.
“Because of his need, humility and will to attain points, it is appropriate to grant him the chance to realise a dream to play in the Champions League in a group that should fight to win it.
“The transfer of an essential player like him can open the door for us to develop a stronger side.”
Darmian will reportedly sign a four-year deal at Old Trafford, where he will undergo a medical on Friday.
Italy’s first-choice right-back, Darmian has attracted the interest of prime European clubs – among them Bayern Munich and Napoli – following a further solid campaign for Torino.
Darmian, who joined Torino from Palermo in 2011, made 32 Serie A appearances in the course of 2014/15.
Club president Urbano Cairo mentioned earlier this week: “It’s standard that an extraordinary man like Matteo desires to attempt and win the Champions League. Torino can not win the Champions League.”
Cairo also warned that any club wanting to sign Darmian must comprehensive the deal ahead of Sunday.
He added: “We are now in extra-time (with regards to the transfer market place) and on Sunday there will probably be the final whistle.”