You have a couple of options. If you're having a cocktail hour, one choice would be to move the toasts to the opening of that time rather than the dinner. It would actually be a nice welcome to the festivities. Another way you could do it would be just after the cake cutting. Assuming it's something all of your guests will be a part of (and since most couples tend to cut the cake on the dance floor, where they're the center of attention). At both times, your guests will be all together and you'll have everyone's attention, so it's the perfect place and time for a few lovely wedding words.
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