Understanding does not mean that you have to agree, endorse, or edify another persons opinion or perspective. Sometimes (often times) understanding is simply listening rather than just hearing.
Understanding is more than just being there. It is being present and aware.
Understanding is not patronizing or sarcastic. It is peaceful, calm, comforting.
Understanding is sticking around when everyone else has gone off to do other things.
Understanding is approaching ideas and knowledge from many angles.
Understanding is multi-faceted.
Understanding grows with time.