Joseph- you said
“bein hasdorim, why is it preferable to prevent the girl from being turned down (rather than the guy)? Is it the emotional issue”
That is because the average bochur has alot more girls being redt to him while the girls aren’t getting redt to as many boys.So if one girl says no to him then he just moves on to the next girl.Boy’s have lists girls don’t unless they are super rich and have the whole world running after them!
I know personally of cases where after the boy gives a yes to a girl, while the girl is checking into the boy, the boy is busy looking into other girls so he has “other girls for backup”