What should I do give up or keep trying?

my coworker introduced me to a woman that works at my job to me it seemed like we hit it off well and got along with each other. I already knew she had a boyfriend but there were some signs that seemed like she was attracted/interested in me. She took time out of her day to hang out with me for a few minutes on my lunch break and she would always stop by my area to talk to me also. Everyday that she saw me she would always have a smile on her face when she said hi. I've had two coworkers tell me that they think she likes me just by the way she acts with me. Things were going smooth for two months until recently when she started to act hot/cold. Some days she'll say hi and talk other days she'll walk right past me like I don't exist and be perfectly fine around other people.
Sn: she has an insecure boyfriend that she is fed up with and trying get out the relationship
What should I do give up or keep trying?
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