Realistically, how do men and women fall in love respectively?

It's immature and pop cultury to find someone special, spend time together, and develop feelings for one another.
Apparently.

yes it is
nobody is special, besides their unique properties (for instance their spatio-temporal properties)

otherwise most properties that people ascribe to others are found elsewhere, it is unwise to doubt this. For example, i like red hair, then if girl A has red hair, most likely there is also a girl B with red hair - this is a heuristic that grossly works

what i am saying is that persons are simply composites of properties, most of the essential ones can be replicated in another person. beliefs, appearance, intelligence, talents ? you can find them in another person, although you probably wont find the totality of what you were expecting, you can find some satisfying similarities. Memories can be transmitted. this night on the bridge with your beloved, you can explain it to your newly found gf while inducing the appropriate emotions: in effect this would be tantamount to have spent this night with her

nobody is special, everything can be replaced

Women are VERY superficial and shallow dude, as is the general person you come across.