A few things. First of all, my desi brothers seem to think that every time a girl smiles at them or stops and says hello, it means she's into him. Guys come on, this is just someone trying to be polite and being themselves. Maybe she's noticed that you are 'too shy' and is just trying to make you feel welcome. Trust me, if she were into you, it would be OBVIOUS.
Secondly, if she's hanging out with some other dude who is married, there's nothing to INTERPRET. She's hanging out with a coworker, absolutely normal. Don't read too much into things.
Lastly, if you like her, it's tough, you WORK with her, if you try anything you might get FIRED.
THANK YOU! I mentioned that as well. It seems like not all consequences are being taken into consideration by the poster.
I have heard of stories where people have complained to their bosses about a co-worker's romantic confessions or inappropriate behavior. There have even been cases where even flirtations can be taken as sexual harassment by some people. Plus, what if you start something with this girl.........and things go sour or you offend her in some way............not only will it be awkward facing her at work............she could potentially try to screw you over at work as well. Just because someone is smiling all the time.....is not a strong indication of their character.
Whatever you decide to do, proceed with caution.