Love is not a bold assumption.
It can be experienced by each person and its existence is inherently known..
Ahhhhh!....There ya go with those assumptions- just bold assumptions.
If love comes down to mere subjective "experience"- I feel it to be true or I feel it therefore it is true...then you just left the door wide open to every other subjective experience (from God to Imortality) that people commonly "assume" to be true.
Loves "existence is inherently known"?....please...find me a country/culture in which 'the afterlife' was not "inherently known".
If we are going by what can be deemed to be "inherently known" to humanity globaly and across the millenia then the 'knowledge' of/belief in the afterlife beats the 'knowledge' of love hands down and by a country mile.
Many Anthropologists/Historians have pointed out that 'love' (especially 'romantic love') as we understand it today is a comparitively recent social construct...belief in ancestor spirits is an "inherently known" back to the dawn of history.