there's not really much you can say at this point so i think you have it right by not replying. "maybe", "probably"...she basically doesn't want to commit time.
mayb i would have sent her something like
"cool, i understand 
anyway, as far as saturday, let me know when you know for sure if you want to do something."
or something like that in your own words. basically I'd put her in a position where she has to either say yes for sure or no she can't. no "maybes". and don't even think about her anymore. if another option on what to do for saturday presents itself, I wouldn't stop myself. And it's also possible she replies "ok" and then never replies. or simply never replies. i'd be ready for that as well. Anyway that's what i would do but i wouldn't say it in a harsh way. everyone has their own style. Only advice i can give you with certitude is not to focus just on her or on what she's thinking.
nah. you're devaluing yourself by saying that. all u gotto say is "sounds good".
when u start saying "i understand" after a girl cancels a date on u or does something similar, you're basically making urself look like you're used to getting that done to you.
when u say "sounds good", u basically leave the ball all in her court and u give the illusion it's whatever to you without actually saying "whatever".
i've had plans set up with a girl once on a saturday afternoon. day came, i told the girl i'm about to get ready and head over to the place we're suppose to meet. she hit me back on some "waitt, relatives just stopped over. i'll let u know when they leave". i responded with an "ok".
the entire day came and went and i didn't hear from her. and i sure as sh1t didn't say anything back to her after the last "ok". she hit me back like a week or so later. to which i didnt even act angry. i was mad. but we were doing this through text so i monitored my words very carefully so she didn't know.
anyway, about 2 months later. we finally meet and i ended up fuccking this chick like several times a weekend for like 4 straight months. during the time we hung out, she said one of the things that drew her to me was "my patience" with her. cause all that cancelling of plans she did, and all that other stuff woulda had most guys acting unbecoming, cussing her out etc. but she was kinda intrigued by my "lack of emotion". a lesson for yall.
for a bit, but I realize that some negative people are meant to be single and alone with ignorance like that. Travel the world and see how women really are, and you will never see your local hood the same again.