Until contracts are exchanged the buyer can pull out at any time – end of. As can you.
Her solicitor **must** tell her that she should not pay a deposit until contracts are exchanged.
Nothing is binding until that point (unless you’re in Scotland of course then its a whole different set of rules) and to hand over money early is fraught with dangers and complications.
Accept her offer, get the ball rolling and tell her if she wants it you need exchange of contracts within two weeks.
Yes, it normally takes between 6 and 12 weeks to reach exchange but her solicitors, if paid enough money, should be able make it happen.
May be delays a) if there are complicated convenants on your property and b) if you property is leasehold.
I used to work in a conveyancing office and if paid enough I have seen offer to completion within 48 hours but it means the solicitor involved dropping all their other cases and working on it 14 hours a day. Hence the cost.
Your solicitor has to do very little as the selling solicitor so should cost you as much.
Cheers
Danny B