Dortmund chiefs have previously discussed interest they received from a "super club" in the spring regarding the former Manchester City youngster.
But Zorc confirmed a meeting was held with Red Devils chiefs during the Inside Borussia Dortmund documentary series, part of Amazon Prime's "All or Nothing" series, filmed back in March.
Zorc said: "A hot topic right now is Sancho and Manchester United.
"Both his discussions with the club and mine with the consultants. A meeting did take place. Manchester United invited the consultant.
"But according to what I know, the consultant told the club that no matter how much money they offer, we won't let him go this summer.
"But the player also has no intention of taking that step this summer."