<human>: I'd met this girl at a park a couple times and been usually friendly. I'm a professional student so I don't have a lot of time to meet people, so I use the park to walk my dog and socialize. I also (something I hate to admit) use Tinder to try and meet girls to possibly date. One day I matched with the girl from the park. She's been talkative, receptive to meeting for dinner, drinks, etc, and our first dinner is supposed to be this week. 

However a cursory search for her facebook resulted in me finding her facebook with her profile picture being her with a guy. I'm not beyond just being friends with this girl, with which I would be okay. But I'm not sure about how I should go about asking her in a non-invasive, polite way of asking if she's seeing somebody and what really are her intentions. How in general is a good way to ask a girl if she's seeing somebody?

Can you summarize the given text in a few sentences?
<bot>: Met a girl, but not sure if she's single or not and would like to know how to be polite in asking what kind of interaction she's interested in.