Sophia Louise was reportedly of a vivid and extrovert personality and "allowed the utmost liberty as regarded her conduct" by her brother, which had caused some gossip.

[1] Sophia Louise's marriage was arranged by the powerful Prussian Minister President Count Johann Kasimir Kolbe von Wartenberg, who pressured King Frederick to marry for the sake of the succession after he had been widowed for a second time.

[1] The king was pleased with her beauty, and after half an hours conversation, the meeting was discontinued, after which the proposal was formally made to the Duke of Mecklenburg-Schwerin and accepted.

According to Pollnitz her Chief Lady in waiting Charlotte Luise "had never left the depths of Wetterau, save to go to the fair of Frankfurt, where she had contracted all the pride of the Imperial Countesses of the Holy Roman Empire, and though she had the best will in the world to act her part, she was far better fitted to figure at Wetzlar (at the Eeichshammergerichte), than at Prussian Court".

Sophia Louise made a great impression upon her marriage and became known as the "Venus of Mecklenburg", and initially, the king was charmed by her beauty and her original extrovert vivacity.

However, aware of the fact that the liberty she had enjoyed at her brother's court had caused gossip about her, she took the advice from Eleonore von Gravenitz to take on a dignified gravity of manner and adherence to religion, which repelled the king, who was himself of an extrovert character and saw her behavior as coldness.

[1] Her Lutheran confessor Porst introduced her to Pietist August Hermann Francke, under whose guidance Sophie Louise grew more serious and strict in her manner, spending her time in a routine of prayers and sermons, managed a court which according to Pollnitz likened to a convent, and was regarded to neglect her representational and social duties as the first lady of the court and female role model.

[1] After this de facto separation from the king, loss of her closest friends and her retirement from court life, Sophia Louisa reportedly became obsessed by religious theology to the point of mania and fell in to depression and mental derangement.

[1] The suddenly awakened king, who suffered from fever, imagined in his confusion that she was the legendary "White Lady" who would foretell his death, and screamed until his attendants appeared, causing a scene.