we were going to quebec for the carnival festival(don't let the name fool you, it's very cold during carnival in quebec 🙂), and i wanted to propose then even though i didn't know her ring size and she knew i didn't know her ring size. the store where i got the ring was very friendly and told me they do resizes free and that if my fiancee didn't like the style of the ring, we could take a new direction when we came back from quebec. so i bought the ring(8 months interest free payment plan) and kept the whole thing secret from everyone except the sales guy.
in quebec one night during a light snowfall, we walked through the old city which had christmas lights on and made for a very lovely setting. we walked down to the bank of the st. lawrence river and i got down on my knee and proposed(in the snow). and at first my wife(gf at the time of course) said "get up out of the snow, what are you doing?" because she thought there was no way i could have a ring since she didn't give me her ring size.
when i pulled out the ring she was shocked to say the least. she started crying in joy and we hugged and kissed and laughed right there for about 30 minutes while i explained the whole story about the resizing and stuff. it turns out the first person we ever told was the night shift concierge at the hotel where we were staying and that because it was so late at night and all the restaurants were closed that our celebratory dinner turned out to be wings, fries and pizza at 2am 🙂
when we got back, the store did indeed resize the ring free, and not only that time but on subsequent visits as well.
ps - my wife used another ring she wore to hold the bigger engagement ring on until the resize.