This means that Diane Guerre is officially Countess Diane de Nassau since her marriage to prince Jean of Luxembourg.
When Prince Louis marries Scarlett-Lauren she and any offspring of the marriage will be at least count(else)s de Nassau but the Head of the Dynasty has the right to confer the style of HRH and title of Prince(ss) de Nassau upon them.
A woman marrying into the family looses the titles if the marriage ends in divorce.
The second wife of Henri's brother Jean so far has not received a title
I did not think so either. But Stefan at the Nobiliana forum pointed out that the court called Diane Comtesse de Nassau in its official communications regarding the 2012 royal wedding guest list and the 2019 list of mourners at funeral of Grand Duc Jean.
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