agree, concur, see eye to eye, be in agreement, be on the same page, think alike
align with - be aligned with - be in harmony with - be on the same wavelength as - be on the same page as - be in tune with - be consistent with - be congruent with
To "be in sync with" someone or something means to be in a state of alignment, harmony, or perfect coordination. It can describe people sharing the same opinion, emotions, or intentions, teams working smoothly toward a common goal, or processes and systems operating on the same schedule or standard. In everyday language it is often used for personal relationships, showing that two people understand each other well or react similarly. In professional or technical contexts, it can refer to synchronized data, schedules, or actions that match in time and content.