META : HE’S GONNA MARRY ME !
god bless you for asking this question . i think all of the lines regarding marriage in the film are incredibly important and speak volumes to both sloane and ferris’ characters . for instance , during the stock exchange scene . ferris’ question seems absent , like saying YOU WANNA GET MARRIED ? to your significant other in high school isn’t a big deal . she seems to take it as a bit of a joke , immediately going along with it as she does with most of ferris’ plans & schemes . i think that’s why he loves her , why he’d marry her . not only does she understand that his personality isn’t going to change for anyone , but she likes that spontaneity , that unpredictability . he doesn’t have to tone himself down for her , and if he ever goes too far she’s logical and grounded enough to talk him out of it . she hasn’t sacrificed her intelligence or personality for him — they compliment each other .
they don’t just contradict each other ; there’s no stark contrast between them . he appreciates that she’s pragmatic but understands that if there was no one like ferris the world would be a terribly sad place . she sees past people’s facades and defenses , even commenting that ferris knew exactly what he was doing when he woke up that morning . he wasn’t just skipping school — he was trying to help cameron and was willing to sacrifice quite a bit to do so .
going back to the stock scene for a moment , there are a few interesting followups to it . for example , when cameron is freaking out , and ferris tells the audience that he wasn’t kidding — he really would marry sloane . you get to see an important piece of his character . he isn’t just a slacker , he isn’t a player and doesn’t want something easy . contrary to what most would believe , he isn’t deathly afraid of commitment . you can also see that he has a bit of a BOY WHO CRIED WOLF thing going on , as even though he’s asking honestly if she would want to get married , ferris says ridiculous things so often she’s become accustomed to them not being serious .
now , to actually answer the question , i think that scene is a beautiful example of how sloane understands ferris and realizes that there is often truth behind his words , that he is soft and modest and quieter with her . i think HE’S GONNA MARRY ME is a realization more than anything , one that shows just how deeply connected ferris and sloane are .