I'm moving my wife from a memory care community in another state to one that is closer to me. What should I tell her to keep her calm?

Since she is already in MC, I would keep your explanation as simple, vague and positive as possible. Have your story and answers ready to keep her as calm as you can. It is possible that she will be quite agitated but I guess it is what it is and she will adjust as well as she is able at this stage of her decline.

Accept the fact that she will likely be confused and/or agitated but that she should do better with enough time in her new location.

When I transferred Mom from my home to and AL and then from AL to LTC we told her she was going to a new apt where she would meet new people.

I think this event gives you permission to use "therapeutic fibs", like telling her you are just visiting or traveling and going to a hotel, or whatever you think will keep her mood stable. You can talk to the admin at the new facility and ask for their advice -- I'm certain yours is not the first case. Will you be able to have the same items in her room set up before she is admitted? Familiarity will help. Or, can you consult with her doctor to see if she can be given a medication just for this day (or week) until she seems more adjusted? I wish you an easy move and peace in your heart.