What does it mean if a woman emails a man to reconnect years later?

How would you as a guy likely respond if at all?

The circumstance was that he really liked her, said so but she was had a partner at the time and so he relocated to a different city.

She tried to contact him via a mutual friend when she split up with him but he never received the message. So now several years later she found him and emailed.. they are both in their early 40s.

What does it mean if a woman emails a man to reconnect years later?
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