So now I think I understand...

[4WayDiablo]

Being work mates would complicate things a little because it it goes royally tits up then you still have to go to work with her

I'd think that if you say you were going to say something g and she defiantly knew something and still wants to hang out a lot then go in for the kill

Failing that go to a party or something, out to the pub. Have a few drinks and get to the point between tipsy and drunk then go in for a kiss. If she refuses then you have your answer then proceed to apologise then blame it on the drink. If she bites then biiiingo .. quids in :-)