I suppose as a private transaction if anything goes wrong, you or the purchaser won’t have any redress through eBay. But from what you’re saying, you seem to be picking up good vibes from your purchaser which is positive!
In your shoes, I would suggest meeting the buyer “in person” and suggesting to her that she views the bag before exchanging money, and then if the sale goes ahead, ask her if you could both go to the ATM together and then you’ll know the money she withdraws isn’t fake. Dunno if that’s feasible due to geography etc!
I’ve only ever purchased from eBay, I’ve never sold anything on it. But I have sold several items down through the years on an Irish website called “DoneDeal”. Fortunately all my sales have been paid for in cash upon handing over the product. I had to correspond with several “chancers” who were trying to bargain me down, even when I clearly stated on the ad that the item was priced at my best price! And I also had to filter out various dopes who wanted to invite themselves to my house at all hours of the night to view the sale item. The process was exhausting and quite stressful!
Are you really sure you want to part with the bag?!
I bought a Marc Jacobs bag on eBay a few years ago. When it arrived I was totally horrified. It was clearly a fake, so cheap looking and so poorly finished. The hardware was like something from the pound store. With PayPal protection I was able to get refunded and to send the bag back too. It put me right off buying any bags from eBay ever again.
Good luck with your decision and with the sale!! I hope you get a fabulous new bag to celebrate!