I believe that reciprocity exists, because reciprocal relationships are complementary relationships that have strong relationships between each other.
Love also won't make people happy
If not based on reciprocal relationships
From the abilities and potential of each individual, love will not last long.
love grows because there is a reciprocal relationship between one another, it will last until the end of time.
A small example if we love someone sincerely, so I'm sure that person will give us the best.