Set up a 4th date with HB9.5. We have have pretty good chemistry. She's smart and very analytical but I think she plays hard to get (She's an old flame - I go into detail in the optional 'background' part of the post below)

The text convo went like this:

• Tuesday afternoon [Me]: I'm going to the fluting paths art installation, its closing tonight. Down?
• Tuesday evening [Her]: Despite the steep stairs and darkness you warned me about I would love to so count me down.
• Tuesday evening [Me]: How's 7:30 sound?
• Wednesday noon [Her]: (after more than 12hr delay) My boss may be temperamental and keep me back. I'll keep you updated if anything changes.
• Wednesday night [Her]: (I’m out with friends and havent responded) Boss just sent an email reminding everyone of the work film screening at meridian. I would be letting the team down if I didn't go.
• Thursday morning [Me]: (I was out all night. I responded the next morning) Don't stress. I know how you dig that team building lovey dovey stuff. Have fun at the film night then.
• Thursday night [Her]: (15mins before we had planned to meet up) my temperamental boss has let me off work early
• Thursday night [Me]: I'm at a dinner in petersham right now. I thought you were attending the film night. I had something urgent to tell you about my pratice (we're both docs)
• Thursday night [Her]: Oh, that was next week. Sorry about the misleading message. Have fun at dinner.

My question is, what is the motive when a girl cancels then pretends not to. And what should the proper response be for something like this in future?

BACKGROUND (OPTIONAL):
Met this girl 4 years ago in med school. We dated for 6 weeks. Lots of chemistry, although we kissed and made out we didn't progress to having sex as she could be quite guarded and hot and cold. After 6 weeks, she had to go overseas for a semester.

On the day she left, she opened up to me for the first time as we sat talking for hours. She admitted that she really liked me and I made her feel nervous which was unsual for her. She seemed to be asking me for an official relationship. I didn't even realise she was asking at the time as I never verbalise boundaries like that, but I guess she was different. But after she left, I didnt hear from her while she was away. I think she found someone else when she was over there.

We argued when she came back and I stopped seeing her. She tried to get back with me for about a month, sending me coy messages of interest, even inviting me out on dates. But I refused to play her hide and seek games anymore.

We don't see each other for 4 years.

In around March this year we began talking over facebook. We make plans to catch up:

1st date: 1 hr work lunch. Just to get to know each other again. We’ve both matured but still have the same chemistry.

2nd date: After work dinner, we as we both agreed the lunch was too short. Basically a 4hr conversation. No kino was possible due to seating, but I didn’t want to at that stage, since I felt like I needed to be cautious around her. She is warm in person but cold over text/phone.

3rd date: All day Saturday date bouncing to various locations. We get along well and there is some kino (brief hand holding, arm in arm etc). I deliberately don’t go for any kiss, since I feel like I’m still sussing her out.

Sounds like a legit cancel on her part. Her boss was keeping her late - sorry she can't make it.

To say it was about the next week is almost laughable.

Motivation could be anything from cold feet to second thoughts... or my gut would tell me it involves another potential date which flaked out on her or didn't pan out.

that's my gut feel too. So that's why I stuck to my original plans and didn't go running to her.

What's the next step? Should I freeze out before waiting for her further response? The problem is, this hb is iron hard and maybe into the Rules. The only time I've seen her initiate a date is when I was trying to cut contact with her 4 years ago.