How does the sister know the sin for which she is being punished, when she does not know what it is?

Repentance from sin is not achieved except through recognizing it, because among the conditions for the validity of repentance are regret, the resolve not to return to the sin, and seeking forgiveness from those whose rights were violated. This cannot be achieved if the sin is unknown.

Therefore, the questioner should strive to recall her shortcomings and transgressions. This is part of self-reckoning, which the predecessors encouraged.

If she is unable to identify a specific sin, then she should make a general, absolute repentance from every sin. This repentance includes a general resolve to perform all commanded acts and abandon all forbidden ones, and a general regret for everything that is forbidden.