<human>: I met this girl at this summer during my part time job. We get close near the end and i begin to be subtle about wanting her. We talk and i flirt a little bit and every seems well received. she laughed at every joke i said even the bad ones. She even asked for my phone and put her number it so we could get food sometime together. So tonight after work i invite her to go get some food with me and she says yes. Its piratically a mini date. 20 minutes in she says so do you have a girlfriend i reply no. I asked her if she has a boyfriends she says YES. In a 2 year relationship with me also. My heart sank and acted normal for the rest of night. She even said we should hang out still. There is no i am going to do that.
Why would a girl do this i made it pretty obvious i was interested and she doesn't tell me about he BF really?

Could you distill the essence of the text into 1-3 sentences?
<bot>: girl put phone number in my phone. go get food together after work only to tell me she has a boyfriends 20 minutes into eating.