Under a new governess, Madame von Sonsfeld, Wilhelmina's lot was much brighter. She says: "Madame de Sonsfeld began by studying my disposition. She observed that I was excessively timid. I trembled when she was very grave; I had not the heart to say two words together without hesitating. She represented to the Queen that it would be proper to divert me, and to treat me with much gentleness, to remove my fears; that I was extremely docile; and that, by exciting my ambition, she might do with me whatever she chose. The Queen left her complete mistress of my education. She every day reasoned with me about indifferent subjects, and endeavoured to inspire me with good sentiments on every occurrence. I applied myself to reading, which soon became my favourite occupation. The emulation which she excited in me made me relish my other studies. I learnt English, Italian, history, geography, philosophy, and music. My improvement was surprisingly rapid; I was so intent upon learning that Madame de Sonsfeld was obliged to moderate my ardour."
An incident showing her excellent memory, altogether remarkable in a child of thirteen, may be mentioned. A certain lady, Miss Polnitz, who was unfriendly towards Wilhelmina, had one day been speaking to the Queen about what she called her ungainly figure. "It is true," said the Queen, "that she might look better; but her shape is straight, and will display itself when she has done growing. However, if you converse with her, you will find that she is not a mere automaton." "Miss Polnitz," continues Wilhelmina, "thereupon began to talk with me, but in an ironical manner, asking me questions which would have suited a child of four years. I was so vexed that I did not deign to make any reply. My sullen behaviour gave her an opportunity to hint to the Queen that I was capricious and haughty, and that I had scrutinised her from head to foot. This brought upon me severe reprimands, which continued all the time Miss Polnitz stayed at Berlin. She quarrelled with me about everything. One day the conversation turned upon powers of memory. The Queen observed that I had an excellent memory. Miss Polnitz set up a malicious grin, as much as to say that she disputed the fact. The Queen, nettled at this, offered to try me, and proposed a wager that I could learn 150 verses by heart in an hour's time. 'Well,' said Miss Polnitz, 'I will try her local memory; and I will bet that she will not remember what I shall write down.' The Queen was consequently very strenuous to maintain what she had asserted, and I was sent for. Having taken me aside, the Queen told me she would freely forgive me all that was past if I proved successful, and so caused her to win her wager. I did not know what was meant by a local memory, having never heard of it before. Miss Polnitz wrote what I was to learn. It was a series of 150 fanciful names of her own invention, all numbered. She read them twice over to me, always mentioning the numbers; after which I was obliged to repeat them in succession. I was very fortunate in the first trial; she desired a second, and asked the names out of order, mentioning merely the number. I again succeeded, to her great vexation. I had never made a greater effort of memory; yet she could not prevail with herself to bestow upon me the slightest commendation. The Queen could not account for her behaviour, and was much offended, though she held her peace."