I hope you lot are correct. We need to get the business done and dusted at least a month before kick off for next season. The tooling about over the last few seasons has cost us in the early part of the season. Tell Dortmund this is the offer yes or no and move on.
You have not understand the transfer policy from Dortmund up to now - there is nothing to tell Dortmund from Manchester United. Dortmund already sets the prize and deadline for Sancho - same like last year - and either Sanchos side (his manager) brings a club who will fullfill exactly what Dortmund wants or he will stay for another year. Dortmund will be happy with this for another year, because he is a garant to achieve their goals. There is no need to sell this player. For Dortmund it is not a problem when United (or any other club) will not pay the expected transfer fee - that is what Sancho knows already.
Another point: Many in this forum compare the PL with the Bundesliga and the way to play, to discuss if Sancho fits for United in the PL. May be most of them did not see many games in the Bundesliga, because it is minimum the same, because there are many teams playing a strong defense, esp. against Dortmund and Bayern. It is interesting to compare the ball-possession: United 56 % - Dortmund 59,5 %, in both leagues there are exactly six teams with less then 45 % of ball-possession (numbers from transfermarkt.com). This means in most games Dortmund and Sancho are playing defense-teams.