To have mutual understanding or empathy; for hearts/feelings to be in tune with each other.
長年連れ添った夫婦は言葉がなくても心が通っていることが多い。
Long-married couples often understand each other without words.
彼とは話していくうちに次第に心が通った。
As I talked with him, we gradually came to understand each other.
地域の行事を通して住民同士の心が通う場が増えた。
Through local events, opportunities for residents to connect emotionally have increased.