1In this case, one may assume that both want to complete the deal at three dinars, and they did not intend to vow but only exaggerated for purposes of bargaining.
2GEMARA: The mishna states: The Sages dissolved four types of vows. Rabbi Abba bar Memel said to Rabbi Ami: You said to us in the name of Rabbi Yehuda Nesia: Who is the tanna who taught this mishna of four vows? It is the opinion of Rabbi Yehuda, who said in the name of Rabbi Tarfon: With regard to two people who entered into a wager, and each declared that he would become a nazirite if the other was right, then actually neither of them becomes a nazirite, because naziriteship is determined only by explicitness of intent. One cannot become a nazirite unless he vows clearly and with certitude. Here too, since the intent of the wagering parties was not actually to vow, the halakha is that the vow is invalid.
3Rava said: You can even say that the mishna is in accordance with the Rabbis, who disagree with Rabbi Yehuda. Does the mishna teach: Both wanted the price to be three dinars? It teaches: Both want, in the present tense, demonstrating that they would have been satisfied with that price from the outset and never intended to vow, so the vow is not binding.
4Ravina said to Rav Ashi: If the seller said to the buyer in the form of a vow that the price must remain more than a sela , and the other declared in the form of a vow that the price must remain less than a shekel, what is the halakha ? Is this a vow, where each stands firmly in his position? Or perhaps this is also merely for encouragement?
5Rav Ashi said to him: We already learned about a similar case: If one was importuning another that he should eat with him and the other refused and said to him: Entering your house is konam for me, or: A drop of cold water is konam for me, and for that reason I will not taste it with you, it is permitted for him to enter his house and drink cold water since he intended it as a vow only for the purpose of eating and drinking a large amount but did not mean literally that he would not drink anything.
6The Gemara asks: And why is this permitted? But he said: A drop of cold water, so how can you say that the vow is only with regard to drinking a large amount? Rather, it must be that a person speaks this way in exaggerated terms but does not mean literally what he says. Here also, in the case of the buyer and seller, a person speaks this way. He exaggerates and does not intend the literal meaning of his words, even though he was quite precise in his wording.
7Ravina said to him: