Gemara

(Beraisa): If witnesses testified for him without his request, he is not lashed and does not pay. She or the Edim Zomemim are stoned.

Inference: Had he requested the witnesses to testify for him, he would be punished even if he did not hire them. This is unlike R. Yehudah:

(Beraisa - R. Yehudah): He is not liable unless he hired witnesses.

(Beraisa #1): A Motzi Shem Ra is lashed and pays 100 Shekalim;

R. Yehudah says, he is lashed in every case. He pays 100 only if he had Bi'ah with his wife.

Version #1: They argue just like R. Eliezer ben Yakov and Chachamim do (on Daf 46a).

The first Tana says that whether or not he had Bi'ah, he is lashed and pays, like Chachamim. R. Yehudah says that he is always lashed, but he pays only if he had Bi'ah, like R. Eliezer ben Yakov.

Version #2: Both Tana'im hold like R. Eliezer ben Yakov.

The first Tana says that he is lashed and pays only if he had Bi'ah. R. Yehudah says that he is lashed in any case, but only pays if he had Bi'ah.

Question: R. Yehudah does not hold that he is always lashed!

(Beraisa #2 - R. Yehudah): He is Lokeh (lashed) only if he had Bi'ah.

Answer #1 (Rav Nachman bar Yitzchak): If he did not have Bi'ah he is lashed only mid'Rabanan.

Answer #2 (Rav Papa): In Beraisa #2 R. Yehudah says that he is Lokeh, i.e. suffers monetarily, only if he had Bi'ah.

Sometimes the Tana call paying money 'Lokeh'.

(Beraisa): Motzi Shem Ra is when a man says "I did not find Besulim in your daughter." If witnesses say that she was Mezanah while married to him, her Kesuvah is 100.

This means that if witnesses say that she had adultery, she is stoned. If they say that she was Mezanah before Kidushin, her Kesuvah is 100.

If his accusation was false, he is lashed and pays 100 Sela'im, whether or not he had Bi'ah with her;

R. Elazar ben Yakov says, this is only if he had Bi'ah with her.

Question: How do Chachamim explain "I did not find Besulim in your daughter"?

Answer: He means, "I did not find witnesses who uphold the virginity of your daughter (through Hazamah of the witnesses who that say that she was Mezanah)."

Question: How do Chachamim explain "U'Forsu ha'Simlah (they will spread the sheet on which they had Bi'ah, to check for Dam Besulim)"?

Answer (R. Avahu): "U'Forshu Mah she'Sam Lah (they will clarify the accusations that he put on her.)"

(R. Yitzchak bar Rav Yakov): Even though the Torah never distinguishes between Bi'ah k'Darkah and Lo k'Darkah regarding lashes or punishments, it distinguishes regarding Motzi Shem Ra. He is punished only if he had Bi'ah k'Darkah (so he can claim that there were no Besulim) and claims that she was Mezanah k'Darkah.

This is like R. Elazar ben Yakov.

Rishonim

Rif and Rosh (4:7): If witnesses say that she had adultery, she is stoned. If they say that she was Mezanah before Kidushin, her Kesuvah is 100. This is not the Halachah. Rather, it was a Mekach Ta'os; she has no Kesuvah. If a man was Motzi Shem (his accusation was false), he is lashed and pays 100 Sela'im, whether or not he had Bi'ah with her. R. Elazar ben Yakov says, this is only if he had Bi'ah with her. He is liable only if he told witnesses to testify, but not if they testified by themselves, and all the more so if no witnesses testified. Motzi Shem Ra is punished only if he had Bi'ah k'Darkah and claims that she was Mezanah k'Darkah. If he did not have Bi'ah, he is lashed mid'Rabanan.

Ran (DH veha'Motzi): The Aruch says that one who transgresses a Mitzvas Aseh is lashed until he dies, without number or estimation (of how many he can bear). The same applies to one who transgresses a mid'Rabanan law. It is called 'Mardus' because he was Mored (rebelled) against Chachamim's words. The Rambam says that the same about one who eats Matzah on Erev Pesach. This is a big stringency of mid'Rabanan laws over mid'Oraisa! However, the Ramah writes that he is lashed with estimation, to be more lenient than lashes mid'Oraisa. This seems correct. However, surely mid'Rabanan lashes for a continuing transgression is until he dies or agrees to accept Divrei Chachamim. Lashes to punish for what was done is according to estimation and is more lenient than mid'Oraisa. We are not particular to use the same whip for mid'Rabanan lashes as for mid'Oraisa lashes.

Rambam (Hilchos Na'arah Besulah 3:1): If a man was Motzi Shem Ra, he is lashed and pays to her father 100 Sela'im of pure silver.

Rambam (10): He is liable only if he had Bi'ah k'Darkah and claims that she was Mezanah k'Darkah. If he had Bi'ah Lo k'Darkah and said that he found that she is not a Besulah, he is exempt, and he is lashed mid'Rabanan.

Rambam (11): If he did not bring witnesses, rather, they testified by themselves, he is exempt, even though the witnesses are killed if they were Huzmu (found to be Zomemim).

Poskim

Tur (EH 177): If a man was Motzi Shem on a Besulas Yisrael, he is lashed and pays to her father 100 Sela'im of pure silver. The case is, he comes to Beis Din and says that he had Bi'ah k'Darkah and did not find Besulim, and brings witnesses of Zenus. If she was Mezanah before Kidushin, she is exempt and she has no Kesuvah.

Question (Beis Yosef DH Keitzad): Why did the Tur say that she has no Kesuvah? Perhaps he means that she does not have a Kesuvah of 200.

Answer (Drishah 3): The Rif, Rosh, Tur and Beis Yosef himself (Siman 67) say that she does not receive even 100, for the Nisu'in was a Mekach Ta'os (she said that she was a Besulah). It is difficult to say that there, he claims Mekach Ta'os and wants to divorce her, and here he merely tells Beis Din what happened and asks if he may keep her.

Tur (ibid.) If she was Mezanah after Kidushin, she is stoned. If the witnesses were Huzmu, he is lashed and pays 100. If he did not bring witnesses, rather, they testified by themselves, and they were Huzmu, they are killed and he is exempt. Similarly, if he says that she was Mezanah Lo k'Darkah and the witnesses were Huzmu, he is exempt. If he did not have Bi'ah, or if he had Bi'ah Lo k'Darkah and was Motzi Shem Ra, even if (he says that) she was Mezanah Lo k'Darkah and his witnesses were Huzmu, he is not liable. He is lashed only mid'Rabanan. I will not elaborate, for it applies only in a Beis Din of 23, which we do not have nowadays.