Rambam’s and Tosefot’s explanations are polar opposites TB Nedarim 8

On today’s daf TB Nedarim 8 Ravina asks Rav Ashi a question. The Ron (ר"ן) shows that Rambam’s and Tosefot’s interpretation of his answer are polar opposites. First the question. “The Gemara relates that Ravina’s wife had taken a vow that he had not immediately nullified as a husband is entitled to do, and she wished to have it dissolved. Ravina came before Rav Ashi and said to him: What is the halakha with regard to whether a husband can become an agent to express his wife’s regret to a court so that they can dissolve her vow?” (Sefaria.org translation) We shall learn later in the massekhet the mechanism how a vow is annulled. The person who makes the vow must regret making it is all we have to know now for a vow to be annulled.

Rav Ashi’s answer at first glance is a head scratcher. “Rav Ashi said to him: If three people who can dissolve the vow (a court-gg) were already assembled, yes; if they are not already assembled, no, a husband cannot serve as an agent to express his wife’s regret to the court.” (Sefaria.org translation) What’s the difference if the court of three which can annul a vow is already assembled or the husband has to go out and assemble it? Rambam and Tosefot answer this question completely differently.

Rambam explains that only the person who makes the vow can express regret with the exception of a husband who may annul his wife’s vows because they are one inseparable unit (ִאשתו כגופו). Nevertheless, Rav Ashi limits this leniency only when the court is already assembled because the woman who made the vow is also there at that time.

Tosefot argues that a man can appoint an agent to express his regret before the court because the man transfers his status to the agent (שליח כמותו). The exception is the husband because he loses all objectivity when comes expressing his wife’s regret. Because the vow affects him as well in a negative way, he will exaggerate his wife’s regret. Secondly, he will act as her agent if it is convenient for him i.e. the court is already assembled. If he has to go out and gather the court, he has had it with his wife and can’t be his wife’s agent for two reasons. He can’t be objective because the vow negatively affects him and he has to go through the pain of gathering a court. (see the Ran on our daf ד"ה בַּעַל מַהוּ שֶׁיֵּעָשֶׂה שָׁלִיחַ לַחֲרָטַת אִשְׁתּוֹ)