What does it mean when a girl calls you "good sir"?

[Anonymous]

So there's a girl who often calls me "good sir" or "kind sir"?

English isn't my first language so I don't even know what they mean and also in what kind of situations they're normally used in the first place. Can someone help me understand this?

[On_cloud_wine]

Sometimes I pretend I live in the 14th century and imitate proper language like “why, thank you, kind sir...* if I’m being flirty, I may just curtsy. ;)

[serious]

I suppose that is a respectful way to address a man.