Must a woman who prayed, believing that what was discharged from her was remnants of istinja', then it became clear to her that it was involuntary urine, repeat the prayer, or is repentance sufficient for her?

If a woman is certain that what was exiting her was urine, then she must repeat the prayers that she is certain were invalid. However, if she is not absolutely certain that urine exited, she is not required to repeat any of the prayers, because the original state is the validity of her purification, and doubt does not remove certainty. Therefore, she should not pay attention to future doubts or whisperings, and she should not rule her purification invalid except with absolute certainty.