Kesubos Chapter 3, Mishnah 1. This chapter deals with a special fine that the Torah imposed on someone who violated a na'arah. A na'arah is a girl who has passed the age of twelve and has developed the signs of physical maturity, and this status lasts only for the first six months, until she becomes a bogeres. If during this period she is a virgin who has not had relations before, then in addition to all the monetary obligations imposed on the offender (embarrassment, damage, and the like), he is also liable for a fixed fine of fifty shekel, which he must pay to her father. This fine is the subject of the discussion in our chapter.
Our Mishnah lists a series of girls whom it is forbidden to marry, and nevertheless the fine applies to one who violates them. The words of the Mishnah: "Eilu na'aros she'yeish lahen kenas" - these are the girls for whom, during the stage of na'arah, the fine applies that the offender must pay.
Girls whom it is forbidden to marry and who nevertheless receive a fine:
"Ha'ba al mamzeres" - a mamzeres is a girl born from a forbidden relationship for which the parents are liable to kares. A Jew may not marry a mamzeres, and nevertheless, if he forced himself upon her, the special fine applies.
"V'al ha'nesinah" - the Nesinim were a group of people who converted under false pretenses in the days of Yehoshua, and therefore a Jew may not marry them.
"V'al ha'Kusis" - a Kusi is one of the inhabitants of Shomron, and the Gemara disputes whether their conversion was valid or not, but in any case it is forbidden to marry them.
"V'al ha'giyores v'al ha'shevuyah v'al ha'shifchah she'nisgayru v'she'nifdu v'she'nishtachreru pechusos mi'bnos shalosh shanim v'yom echad" - in the case of the convert, this refers to a convert whom he is permitted to marry; in the case of the captive, a woman who was taken captive and then redeemed; and in the case of the maidservant, a maidservant who was freed. In all of these the condition is that the change of status - the conversion, the redemption, or the release - took place while she was under the age of three years and one day.
And as we have already learned, below the age of three relations are not considered valid relations, and she remains a virgin. Since one of the criteria for the fine is that the girl be a virgin, therefore, even though ordinarily a woman who had been a gentile, a captive, or a maidservant is presumed not to be a virgin, here, since she left that status before the age of three, we assume that she is still a virgin.
Forbidden relations for which one is liable to kares:
"Ha'ba al achoso" - for whom he is liable to kares.
"V'al achos aviv".
"V'al achos imo".
"V'al achos ishto".
"V'al eishes achiv".
"V'al eishes achi aviv".
"V'al ha'nidah" - even a girl who is in the status of a nidah.
"Yeish lahen kenas, af al pi she'hen b'chares - ein bahen misas beis din" - in all of these the fine applies. True, the relations listed in the last group all carry liability to kares, but the liability to kares does not cancel the monetary obligation. The emphasis that they do not carry court-imposed death is necessary, for if the offense were one punishable by death, the principle of "kim lei b'draba minei" would apply - that he receives only the more severe punishment, namely death, and not the monetary penalty. But since these cases carry no death sentence, only kares, he remains obligated to pay.
In summary: In this Mishnah we learned who the girls are that receive a fine - those whom it is forbidden to marry (a mamzeres, a Nesinah, and a Kusis), the convert, the captive, and the maidservant whose status changed before the age of three and who are therefore presumed to be virgins, and the forbidden relations for which one is liable to kares. In all of these the fine stands, since liability to kares does not exempt one from the monetary obligation, and only court-imposed death would have exempted him by force of the principle "kim lei b'draba minei".