Only God knows TB Yevamot 112

The exact meaning of something a woman says on today’s daf TB Yevamot 112 is a matter of debate amongst the commentators.

We learned in a mishna elsewhere (Nedarim 90b): At first they said: Three categories of women are divorced from their husbands against their will, and even so they receive payment of their marriage contract...Likewise, a woman who says: Heaven is between me and you-הַשָּׁמַיִם בֵּינִי לְבֵינָךְ” (Sefaria.org translation)

Rashi explains this expression “Heaven is between me and you” to mean that only God knows that the husband is incapable of having normal sexual relations with her. In a similar vein the Yerushalmi (Nedarim chapter 1, halakha 1) give this explanation “Just as Heaven is far from Earth, my husband has been far from me.”  Tosefot provides a third explanation quoting TB Nedarim 90b “he does not shoot like an arrow, i.e., his semen is not emitted forcefully,” (Sefaria.org translation)

Even though the exact meaning is unclear, we understand what the woman is claiming. The sexual relationship between the husband and wife is private, consequently, there are no witnesses to testify to the truth of her statement. Only God is capable knows the truth of the matter.