Could Daenerys marrying Jon get Sansa to agree to the North as part of the Seven Kingdoms?
Sansa made it clear she will not accept Daenerys ruling the North when all is said and done.
A Jon Snow/Daenerys marriage has already gotten bandied about in the final season.
In the Season 8 premiere, Davos talked to Tyrion and Varys about it, suggesting that a marriage alliance would quell tensions between the North and Daenerys being their Queen.