Shevuos, Chapter 4, Mishnah 4. The Mishnah continues to clarify which claims are included in the oath of a deposit and which are not.
The case before us: a person claims against his fellow, "anasta u'fitisa es bitti" - "you raped and you seduced my daughter" - a claim for which the Torah imposed a fine of fifty silver pieces. The defendant answers, "lo anasti v'lo pitisi" - "I did not rape and I did not seduce"; the claimant says to him, "mashbi'acha ani" - "I impose an oath upon you," and the defendant answers "amen" and accepts the oath upon himself. Afterwards he admits that he swore falsely - and thereby becomes obligated to bring a korban for the oath of a deposit.
The view of Rabbi Shimon:
Rabbi Shimon exempts him from the korban, and his reasoning is: "she'eino meshalem kenas al pi atzmo" - "because a person does not pay a fine on the basis of his own admission." The claim here is not for money that the defendant owes, but for a fine that the Torah imposed as a result of the act, and the halachah is that one who admits to a fine is exempt - one who admits to an act that carries a fine does not pay. It emerges that when the defendant denied the obligation, there was no denial of money at all: after all, he could have freed himself from payment by admitting alone, and if so, he is not denying something that he actually owes.
The response of the Sages:
The Sages said to him: "af al pi she'eino meshalem kenas al pi atzmo - meshalem boshes u'fegam al pi atzmo" - "even though he does not pay a fine on the basis of his own admission, he does pay for humiliation and damage on the basis of his own admission." That is, besides the fine of fifty silver pieces, the claim also includes a monetary demand: payment for humiliation - for the shame he caused, and for damage - for the reduction in her value. These obligations are not a fine but ordinary money, and one who admits to them must pay. It emerges that in his denial he denied money, and therefore he is obligated to bring a korban for the oath of a deposit.
The root of the dispute:
One must ask: why did Rabbi Shimon not take into account the payments for humiliation and damage, when he too agrees that they exist?
The Gemara explains that Rabbi Shimon holds that when a single claim includes a fixed sum set by the Torah alongside an indefinite sum that depends on the assessment of the court, the claimant focuses his claim specifically on the fine - for that is the known and precise amount, and it is the essence of his demand. The other sum he is not really claiming, and so it emerges that the denial relates to the fine alone; and since a person does not pay a fine on the basis of his own admission, there is no denial here of money that he owes.
The Sages disagree and hold that the claimant intends both elements together - both the fine and the humiliation and damage. Consequently, the denial includes a denial of the payments for humiliation and damage as well, which are a full monetary debt, and therefore he is obligated because he swore and denied money that he owes.
In summary: in this Mishnah the Tannaim disagree regarding one who claims "you raped and you seduced my daughter" and the defendant swore falsely: according to Rabbi Shimon he is exempt, since the essence of the claim is a fine, and a person does not pay a fine on the basis of his own admission - so there is no denial of money here. According to the Sages he is obligated, since the claim also includes payments for humiliation and damage, which are money that is paid on the basis of one's own admission, and it emerges that he denied money that he owes.