You will probably win, or at least seem to have  the odds in your favor:1) Typically, deposits are not refundable when the customer cancels; usually, they rare refundable when the business/contractor can't or won't carry through or do the work. So assuming she admits that she cancelled, right there, the presumption is that the deposit is non-refundable.2) As the person suing, the burden of proof is on her; that means that she needs to be *more* believable or credible than you--not by a lot, but at least by a fraction. If the two of you are equally credible, you win.