KABUL, Afghanistan — When the Afghan government announced Thursday that it would pardon a woman who had been imprisoned for adultery after she reported that she had been raped, the decision seemed a clear victory for the many women here whose lives have been ground down by the Afghan justice system.

But when the announcement also made it clear that there was an expectation that the woman, Gulnaz, would agree to marry the man who raped her, the moment instead revealed the ways in which even efforts guided by the best intentions to redress violence against women here run up against the limits of change in a society where cultural practices are so powerful that few can resist them, not even the president.