Imagine an AU where a large part of the dating is tied to this socially hyped personality test. Think Meyers Briggs type test.
This test is in place just for the people in society to categorize their feelings on what the test says. This trait and style had been taken on and adapted through many years and no one has strayed from this method on finding love or even just a temporary partner. (Character in book) manages to see past this by not centering with everyone else's thought process or behavioral pattern.