She was introduced to Henry when he visited Kassel in 1751 and was married to him on 25 June 1752 at Charlottenburg Palace.

Wilhelmina had no children with Henry, who was reported to pay more attention to his male friends than to her.

After the separation, she lived at Prince Henry's Palais in Berlin, on the grand boulevard Unter den Linden, which the king had built for his brother between 1748 and 1753 (today the main building of the Humboldt University of Berlin).

The Swedish princess Hedvig Elisabeth Charlotte of Holstein-Gottorp described her at the time of her visit in 1798: She was a tall and handsome lady with a well kept figure, though very thin, and you can still see how remarkably beautiful she was in her youth.

While most of the royal family left, reportedly because of the anti-Napoleonic criticisms they had expressed, and the members of the royal court either followed them or left the capital for their country estates, Wilhelmina remained with Prince Augustus Ferdinand of Prussia and his consort Margravine Elisabeth Louise of Brandenburg-Schwedt because of "their high age" as well as Princess Augusta of Prussia, who was pregnant at the time.