熬成旧友
[áo chéng jiù yŏu]
'Turned into An Old Friend' symbolizes deep friendship that has stood the test of time. In most cases, it implies that two individuals who once had a special relationship (possibly romantic), have chosen (or due to circumstances) transitioned that connection into a friendship characterized by warmth and familiarity without passion - becoming old friends who cherish each other's company even if the original reason they met fades.