How should I write the time on the invitations to assure that all the guests arrive on time?

While there’s no way to assure that your guests will arrive on time, there are ways to make sure your wedding ceremony begins on time. The best way to do this is to make the start time on the invitations an hour earlier than when the ceremony is set to begin. In this hour you can have waiters serve drinks and h’ordeuvres. This gives your guests a grace period if they’re running late as well as a chance to chit chat, use the restroom, and feed their rumbling tummies. That way all your guests will be seated and content by the time the ceremony commences.