(Mishnah): What are vows of Inuy Nefesh? She said 'Konam, Peros of the world are Alai', he can annul it.

'Peros of this region are Alai', (he cannot annul. Rather,) he brings to her Peros of a different region;

'Peros of this grocer are Alai', he cannot annul. If his Parnasah (all his food) is only from him, he can annul; R. Yosi says so.

(Gemara - Shmuel): If she said, 'Konam, Peros of the world are Alai', and there were Peros hidden in a storehouse, he buys for her from them (she did not intend to forbid them).

(Reish Lakish): 'Peros of people of this region are Alai', and there were visitors there selling, he buys from them.

It is written "Kol Neder v'Chol Shevu'as Isar Le'anos Nafesh", e.g. peppers that I will not taste, onions that I will not taste (even though it is a small affliction);

It is not only if there is that species [in the region]. Rather, even if that species is not [in the region], perhaps someone else will bring to her that species.

(R. Yochanan citing R. Yanai): If there were two pieces in front of him, one good and one bad, and she put her eye on the good, and vowed from the bad, he can annul.

Question: Why can he annul?

Answer #1 (Talmidim): It is due to her Inuy Nefesh (perhaps she will want to eat both of them).

Answer #2 (R. Ze'ira and R. Heila): It is due to his Inuy Nefesh (really, it is matters between him and her. Due to her vow, he must leave the good one for her.)