All royal wifes bear their husbands full title?
For example:
HRH Countess of Wessex: is Princess of UK of GB & Viscountess of Severn, too?
HRH Grand Duchess of Luxembourg: is Duchess of Nassau, Countess of Sayn, Königstein, Katzenelnbogen & Dieza, Viscountess of d'Hammerstein, etc.
HSH Fürstin...