Sónya's letter written from Tróitsa, which had come as an answer to Nicholas' prayer, was prompted by this: the thought of getting Nicholas married to an heiress occupied the old countess' mind more and more. She knew that Sónya was the chief obstacle to this happening, and Sónya's life in the countess' house had grown harder and harder, especially after they had received a letter from Nicholas telling of his meeting with Princess Mary in Boguchárovo. The countess let no occasion slip of making humiliating or cruel allusions to Sónya.
But a few days before they left Moscow, moved and excited by all that was going on, she called Sónya to her and, instead of reproaching and making demands on her, tearfully implored her to sacrifice herself and repay all that the family had done for her by breaking off her engagement with Nicholas.
"I shall not be at peace till you promise me this."
Sónya burst into hysterical tears and replied through her sobs that she would do anything and was prepared for anything, but gave no actual promise and could not bring herself to decide to do what was demanded of her. She must sacrifice herself for the family that had reared and brought her up. To sacrifice herself for others was Sónya's habit. Her position in the house was such that only by sacrifice could she show her worth, and she was accustomed to this and loved doing it. But in all her former acts of self-sacrifice she had been happily conscious that they raised her in her own esteem and in that of others, and so made her more worthy of Nicholas whom she loved more than anything in the world. But now they wanted her to sacrifice the very thing that constituted the whole reward for her self-sacrifice and the whole meaning of her life. And for the first time she felt bitterness against those who had been her benefactors only to torture her the more painfully; she felt jealous of Natásha who had never experienced anything of this sort, had never needed to sacrifice herself, but made others sacrifice themselves for her and yet was beloved by everybody. And for the first time Sónya felt that out of her pure, quiet love for Nicholas a passionate feeling was beginning to grow up which was stronger than principle, virtue, or religion. Under the influence of this feeling Sónya, whose life of dependence had taught her involuntarily to be secretive, having answered the countess in vague general terms, avoided talking with her and resolved to wait till she should see Nicholas, not in order to set him free but on the contrary at that meeting to bind him to her forever.
The bustle and terror of the Rostóvs' last days in Moscow stifled the gloomy thoughts that oppressed Sónya. She was glad to find escape from them in practical activity. But when she heard of Prince Andrew's presence in their house, despite her sincere pity for him and for Natásha, she was seized by a joyful and superstitious feeling that God did not intend her to be separated from Nicholas. She knew that Natásha loved no one but Prince Andrew and had never ceased to love him. She knew that being thrown together again under such terrible circumstances they would again fall in love with one another, and that Nicholas would then not be able to marry Princess Mary as they would be within the prohibited degrees of affinity. Despite all the terror of what had happened during those last days and during the first days of their journey, this feeling that Providence was intervening in her personal affairs cheered Sónya.
At the Tróitsa monastery the Rostóvs first broke their journey for a whole day.