The only people who understand you without you speaking a word are people who have known you a long time.

It's impossible to understand another until you cease to judge both them and yourself. Then and only then can they fill the small emptiness inside you that has been waiting for them.

mostly not wanting to understand

I had a memorable taxi-ride many years ago.
The poor taxi-driver was complaining how his beautiful wife hardly ever had sex with him any more, and he was thinking of finding a mistress. The classic timeless story.
He even actually uttered the ultimate cliche "My wife doesn't understand me anymore"

I told him from my experience that "a bit on the side" created more problems than it solved.

Then I had this amazing clarification sweep through my mind, like I had the answer to both our problems. I said "There is No-one on Earth that understands you. There are only people that you have some things in common with, who will gradually understand you in time, if you can put up with each other long enough".

And of course, if I had been his therapist, I could have quizzed him about how much he understood his wife.

Anyway, I have never forgotten this little "insight" all those years ago. I have to keep reminding myself of it from time to time, and stop trying to find "the one", and keep an eye out for "the likely one".

Tim Minchin had this interesting take on the challenge

Thats why opposites don't attract. When something gets tough the other don't understand.

They're rare. Very rare.