Two Requests are Enough

I asked this tiny, delicious, petite lady at work, out twice since I received positive signs from her but didn't get anywhere. Women change their mind on daily basis! One day they like you and 20 minutes after that they barely look at your face. I decided to drop the case and just say nothing. I only sent her a message on Easter and that was it. I received a response but it was just a response. Nothing to say that she would like to meet or anything. So the entire time after that I didn't even get a chance to say Hi. I only noticed her looking at me twice. Looked like that I still have to step forward and add something! But I won't. I have initiated the action after receiving what I thought at the time to be a good sign and now is her turn. I'm not a type of guy who negs women. Now when I see her again at work when we have a chance to talk, I will only politely say Hi and ask how she is. If she's interested she will tell me that she would like to go out with me on this day and if she's not, she'll remain only a person at work and not even a collogue because we don't even work together.  
The funny thing is one of the guys that I at times, talk to, told me that he had been told by her that she has a bf! When I told him that she has never said that to me and I even had been given her number and we were supposed to go out, he was shocked but promised me not to say anything to anyone else in the company. She had told him that she had been invited to a dinner by her bf, recently! That would have been me! My guess is either she has a bf whom she's trying to replace him and the was why she was nice and seemed wanting(!) to me or she has found someone else who she thinks is better than me!