I want to answer:
After the other one asks me questions which lead me to the point where I can see clearly and understand myself. The sharper the questions are the better. The more inconvenient they are, the better I come to the truth - then the longing stops.
I feel understood when I can sense interest from the person I am with. That he or she questions my motivations without having an own idea about how my answer should be. In those moments I feel deeply understood. It doesn't come immediately, in particular, when I felt cornered or pressured. More easily and immediately: Having been understood is created through those open and calm questions I can openly and calmly respond to.
So, questioning signals me the other truly understands me (he wouldn't ask if not).
Also, the feeling of having been understood comes through artworks from others (music, texts, paintings, pictures, architecture, songs etc.) - then I long for telling the other one how much I love his/her piece.
I am talking about all people I am engaging with. Every encounter has the potential to understanding. On whom I am focusing on, that is the person I like to understand me. To a degree that I can feel satisfaction (leaving the scene without wanting more or less from the other).
In answering your questions a good thing happens: I notice that I already had this experiences of me feeling totally understood by people. Close ones as well as strangers. And that I can stop being needy. Also, that, in the end, it's not the other who must understand me but I myself. This is not new to me but still not bad to repeat it often enough (and, probably even more frequently).
I notice as well that wanting to renew "being understood" has to do with occasions and the ever-changing life. During work and private encounters, it is needed to make oneself clear.
Understanding happens in every moment of my life.
Thank you, that was a welcomed service for me. You talked to my higher self (inner authority, you name it). It changed my morning and will have an influence on the day. Until the next moment is going to hit me, where I feel misunderstood:=D ... will then hopefully be so geistesgegenwärtig (German for ... "spiritually aware") that I'll remember the learning.
Thank you.