The problem I have with this thread is that it seems to assume that the only objects of understanding are people.
It's a good point. I hadn't thought of that. I was, indeed, focusing human beliefs and interpersonal dynamics.
What about understanding nature, or abstract ideas, or music?
These are much less complex and easier to understand, than an individual's POV and beliefs?
If so, then I think
@Quintessence's query about what one means by love is apposite.
Agreed.
Perhaps I can ask the question a little differently? True understanding, real complete understanding, is impossible, IMO. No one can learn every aspect, every detail, of someone ( or something ) 100%. The best anyone can do, is approach understanding. How does this happen? What is the cause, the inspiration, the motivation behind the impulse to learn about someone ( or something ) that is external the the individual? It could even be self discovery... It's curiosity? sure. But if it's only curiosity, then the inspiration/motivation/impulse to learn is shallow and brief? If so, then curiosity alone doesn't approach understanding in a significant way. It's only scratching the surface.
So what brings a person to a deeper understanding? In every example that I can think of, compassion and empathy are at least involved. How much are they involved, and whether they are required is the question I was trying to ask in the OP.