Is it permissible to refuse marriage to a young man who proposed to me—despite my initial agreement under family pressure—due to an absolute lack of desire to marry, and will I be held accountable for this, similar to the story that occurred during the time of the Prophet, may Allah’s prayers and peace be upon him, when he said to a man who complained to him about his daughter’s refusal to marry: "Leave her"?

If a woman receives a proposal from a man whose religiosity and character she is pleased with, she should accept him, acting upon the Prophet's (peace be upon him) recommendation. However, this is a matter of recommendation, not obligation, so there is no sin upon her or her guardians if they reject the suitor. Nevertheless, it is not permissible for a woman to completely abandon marriage if she fears falling into the unlawful. Marriage is the sunnah of the Messengers, and through it, half of one's religion is perfected. Our advice is not to turn away from marriage, nor to reject a suitor who possesses religiosity and good character. The story you mentioned about a woman refraining from marriage is not true.