86a
Acc to man deomar that we are not cholkin maaser in bais hagronos because of yichud. Then what does this mishna have anything to do with a bas levi married to a kohen, this din has nothing to do with marriage! Even a penuyah is ossur in yichud cos of gezera of dovid hamelech?
Even if it has to do with yochud deoiraisa of a married woman, it has nothing to do with marriage of a leviis to kohen?
(As opposed to the other man deomar, there's a chiddush that a bas levi is also considered a potential gerusha for this din)
Avrumi Hersh, London england
1) The Mishnah is not discussing a Bas Levi married to a Kohen. It is discussing a Bas Levi who had Erusin with a Kohen, not Nesu'in.
2) Mar brei d'Ravana said that when the Mishnah stated that a Bas Levi who had Erusin may not eat Terumah, this does not mean that she may not eat Terumah at all, but it means that we do not give her Ma'aser in the Beis ha'Gronos. Now the Gemara examines whether Mar brei d'Ravana's statement is consistent with the Mishnah. The Gemara says that according to the opinion that the reason why the Beraisa below (99b) states that one may not give Terumah to a woman in the Beis ha'Gronos is because of Yichud, Mar brei d'Ravana's statement is consistent with the Mishnah, because the Bas Levi who did Erusin with the Kohen also has a problem of Yichud. However, according to the opinion below (100a) that the reason why one may not give Terumah to a woman in the Beis ha'Gronos is because of Gerushah, the Gemara here says that Mar brei d'Ravana's statement does not fit the Mishnah because the Bas Levi may eat Ma'aser even after she is divorced.
3) So, indeed Yichud always applies as a valid reason that one may not give Terumah to a woman in the Beis ha'Gronos. But the question of the Gemara was on the other Man d'Amar. If the reason is because of Gerushah, then Mar brei d'Ravana's statement cannot work, because a Bas Levi can always eat Terumah, whether married or divorced.
4) Is there a prohibition to give Terumah to a Penuyah in the Beis ha'Gronos because of Yichud?
The Aruch la'Ner here cites Rashi below (99b, DH veha'Ishah) who writes that the woman referred to in the Beraisa there (that one may not give Terumah to a woman in the Beis ha'Gronos) is the wife of a Kohen. The Aruch la'Ner suggests that this implies that one may give Terumah to a single woman, since the prohibition for her in Yichud is only mid'Rabanan. However, the Aruch la'Ner then questions this proof and remains in doubt about our issue.
(See also the Aruch ha'Shulchan ha'Atid, Zera'im, Hilchos Terumos #51, and end of #85, and see the Teshuvos Shevet ha'Levi 2:186.)
Kol Tuv,
Dovid Bloom