Ahhh I understand! Then she needs educating in the ways of the Scot!
Spend the next week sleeping on a park bench, drinking nothing but special Special Brew... Avoid washing, naturally, and upon her return, turn up at the airport drunk covered I'm vomit and tell her how much you love her and that you want to marry, and that you've pawned the ring to buy a can of Tenants Super... Offer her a sip and to highten the effect, try soiling yourself durning the more elucid moments of the proposal...
If she says yes after that, I'd say you're on a winner!