I received this reply from Liechtenstein. I have written to Prince Hans-Adams II & Princess Marie in July for their 50th (Golden) Wedding Anniversary! Prince Hans-Adams is the monarch of Liechtenstein. But he retired in 2004 and made his son, Prince Alois, regent.
This reply came just over 2 months after I wrote. That's a pretty normal response time for royal mail in general. But it's the longest wait time I've ever had for a reply from Liechtenstein.
The front of the envelope is the usual from the Liechtenstein Royals.
Many thanks for your kind wisheson the occasion of ourGolden Wedding AnniversaryMarie Liechtenstein Hans Adams Liechtenstein
You may notice that the card uses two different fonts. The Liechtenstein Royals have pre-made cards that just say "Many thanks for your kind wishes." These are able to be used for almost any event. The 2nd & 3rd line were added later to make this card specific for their 50th wedding anniversary.
The signatures appear to be real as they differ from the signatures I have on other cards from them.