There is a stunningly beautiful girl at my new job...

Who cares if she has a boyfriend go ahead and become her work husband. She already spends more time at work with you, don’t fumble this one
 
She's very shy and I don't want to scare her.
Shy girls like the assertive guy. You gotta get in there. Like celidheere said if you get closer to her you can finesse your way of asking her if she's got somone by asking a roundabout question e.g. ask her what she does outside of work etc
 
Is this job going to be long term? My advice don’t shit where you eat. Also someone higher up then you can be eyeing her as well and will f*ck you over , or put a bad word around you in work to cock block you.
 
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