What causes a girl to be quiet towards a guy?

This girl is quiet towards me and only me 😭 I've only ever been nice to her. For reason she is acting quiet towards me. She will comfortably engage in other guys easily. But with me she is quiet. I've tried engaging with her in conversation. I still get the quietness from her. But then she'll happily help me with things i didn't ask for. What is going on? I must be shit or something 😭

What causes a girl to be quiet towards a guy?
Post Opinion