Shortly after the birth of her second son Alfred in September 1808, the couple took up places in the royal court: Diana as lady-in-waiting to Queen Catharina, Wilhelm as chamberlain to Jérôme.

While her husband spent his time at various health spas, and her two sons Gottfried and Alfred stayed with a retired priest in the Harz mountains, Diana enjoyed life at the court of "King Funny".

In August 1809, the Parisian ambassador in Kassel, Karl Friedrich Reinhard, reported that Pierre had separated from Diana due to his marriage to the Countess Adelheid von Hardenberg.

Pierre had raved of Diana's charms to the king, which awakened Jérôme's interest; his advances were initially resisted, as Reinhard pointedly noted in a letter dated 10 August 1809.

Barely three months later, on 30 November 1811, Wilhelm was raised to the rank of Count in the Westphalian court, most likely done in response to the birth of the daughter, who was most likely the king's illegitimate offspring.

The child, named Marie Pauline von Schönfeld after her birthplace, was secretly taken to the monastery of Notre Dame des Oiseaux in Paris; she was brought up there as well as with Diana's relatives in Alsace.

After her husband's death in 1815, Diana took her daughter Jenny back to Weimar, where her sister Isabelle had married the General, Count August Karl von und zu Egloffstein.

Since the Grand Duchess Maria Pavlovna, whom she had previously served as lady-in-waiting, welcomed her back with open arms, her position in Weimar society was secured.

In the autumn of 1815, she met the widowed diplomat and later Minister of State Ernst Christian August von Gersdorff (1781–1852), who had been a part of the Sachsen-Weimar-Eisenach delegation to the Congress of Vienna and had just returned to Weimar.