How do I understand a girl?

Hello! I have this question, how do I understand a girl? And what she wants to achieve? I met a girl, moved to live with her in another city, rented an apartment, lived for 2 months, then there were financial difficulties, and I had to leave. We did not correspond for three months, then I wrote her a sms that I still have feelings for her, in response I received a sms that she loves me, waits for me, cannot live without me, and says that I must come and wait! A week later, she says she is moving to another man to live with her! How can I understand her? What does she want to say? Thank you.