Ketubot

He who says. I have found an 'open opening'  is trusted to make her forbidden for him.  Why?  It is a double doubt:  It is a doubt [whether she had the intercourse with the other man while] under him,  or,  [while] not under him.  And if you say  that [she had that intercourse while] under him, [there is] the [other] doubt [whether she had that intercourse] by violence or  by [her free] will! — It was necessary  [to state this rule] in the case of the wife of a priest.  And if you wish, you may say [that it speaks of] the wife of an Israelite,  and for instance when her father received the betrothal for her [when] she was less than three years and one day old.  What does he  let us hear by [this since] we have already learnt [it]:  'If a man says  to a woman, "I have betrothed thee [to myself]", and she says, "Thou hast not betrothed me [to thyself]," she is allowed [to marry] his relatives, but he is forbidden [to marry] her relatives.'  — What you might have supposed is that there  [he causes a prohibition to himself] because it is certain to him,  but here it is not quite certain to him.  [Therefore] he  lets us hear [this rule].  But did R. Eleazar say so? Did not R. Eleazar say: The wife does not become forbidden for her husband save in the case of  warning  and seclusion,  and as [we find in] the occurrence that happened?  But how can you [in any case] understand it?  Was the occurrence that happened accompanied by warning and seclusion? And again, did they  declare her  forbidden?  — This is no difficulty, [for] thus he  means to say:  The wife does not become forbidden for her husband save in the case of warning and seclusion, [and this we learn] from the occurrence that happened, because [there] there was no warning and seclusion and [therefore] she  was not forbidden.  But [the former question] is nevertheless difficult. In the [case of] warning and seclusion but not [in the case of] 'an open opening'!  — But according to your argument  [the question could be asked]: [in the case of] warning and seclusion, yes, [and in the case of] witnesses,  no! Hence he  means to say thus: The wife does not become forbidden for her husband through one witness  but through two witnesses;  but in the case of warning and seclusion:  even through one witness,  and 'an open opening' is like two witnesses.  And if you will say: [In the case of] the occurrence that happened. why did they not declare her forbidden?  [The answer is:] There it was compulsion.  And if you wish you can say as R. Samuel the son of Nahmani said  [that] R. Jonathan said: