The Ramban points out the uniqueness of Parshas Sotah. This ritual, which determines the fidelity or infidelity of a wife suspected of adultery, is the only mitzvah in the Torah that functions via the performance of a nes nigleh (open miracle). Explicit Divine intervention does not occur by our carrying out of any other of the Torah’s prescribed mitzvos.
Rav Yaakov Kamenetsky explains that the reason for this is to demonstrate to us the great importance of shalom bayis (domestic tranquility). If a husband suspects that his wife was unfaithful to him, even if she produces two witnesses that she was not unfaithful, he still may have lingering doubts in his heart: Can I really trust her? This would cause a reticence on the part of the husband in their relationship. The only thing that could fully dispel such suspicions, removing any and all doubts, is the Ribbono Shel Olam Himself testifying in a miraculous and dramatic fashion about the innocence of the suspected adulteress. By virtue of the fact that she was not negatively affected by drinking the “bitter waters,” the husband fully realizes that his suspicions were unjustified, and that his wife had not been unfaithful.
However, there is another issue that we need to understand here. The pasuk says that if the “bitter waters” prove that she had been inappropriately suspected, then, as a reward for undergoing this ordeal, she will experience much easier childbirths in the future, her children will be more beautiful than before, etc. However, this woman was still no tzadekes! This is a married woman who secluded herself with another man, in violation of her husband’s warning and in violation of a Torah prohibition! Why should she merit these berachos just because the waters proved that she did not commit actual adultery with the gentlemen with whom she allowed herself to be secluded?
This lady is not Rebbetzin Kanievsky or Sara Schenirer! Why should she be reaping such rewards?
The Ibn Ezra explains that these berachos are compensation for the embarrassment she endured. As compensation for the humiliation that she experienced, Hashem gives her a berachah: You will have an easy time in childbirth, etc.
