Before us is Mishnah 2 in chapter 11 of Maseches Kesubos. This Mishnah addresses the question of when a widow collects her kesubah or her maintenance, that is, the money designated for her food, and in which circumstances she must do so in beis din and in which circumstances she may do so even outside of beis din.
The View of the First Tanna:
The Mishnah states: "Almanah, bein min ha'irusin bein min ha'nisu'in, mocheres shelo b'veis din" - a widow, whether from betrothal or from marriage, sells outside of beis din. There are two situations here:
A widow from betrothal: a woman who was widowed while still betrothed, before she was married. In this situation she has no right to maintenance, since maintenance is granted to a woman only after marriage: because the husband was obligated in her maintenance during his lifetime, the obligation of maintenance falls upon his assets even after his death. But if she had no maintenance during his lifetime, as is the case during betrothal, she has no maintenance after his death either. Therefore she sells from the assets of the estate only in order to collect her kesubah.
A widow from marriage: a woman who was widowed after the marriage, and she may sell from the assets of the estate both for maintenance and for her kesubah.
In both situations alike, the first Tanna holds that she may carry out the sale even outside of beis din.
The Reason for the Permission to Sell Outside of Beis Din:
The Gemara explains the reason: "Ein adam rotzeh she'tisbazeh ishto b'veis din" - a man does not want his wife to be degraded in beis din. Out of the husband's concern for his wife's dignity, he does not want her to be forced to suffer the indignity of appearing before beis din. For this reason she is permitted to sell outside of beis din. Nevertheless, she must still sell in the presence of three people who are expert in the appraisal of land.
The View of Rabbi Shimon:
Rabbi Shimon disagrees with the first Tanna and distinguishes between the situations: "Min ha'nisu'in mocheres shelo b'veis din" - a widow from marriage, who sells from the assets of the estate for her maintenance, may sell outside of beis din, since she cannot wait and she needs her food immediately. "Min ha'irusin lo timkor ela b'veis din, she'ein lah mezonos" - a widow from betrothal, who has no right to maintenance and is selling only for her kesubah, may sell only in beis din, since the kesubah is not an immediate need, unlike maintenance.
It emerges from here that according to Rabbi Shimon, only an immediate need constitutes grounds for a sale outside of beis din. He does not accept the reasoning that a man does not want his wife degraded in beis din, and therefore any woman who is not selling for maintenance but only for her kesubah may sell only in beis din.
A Point Left Open in the Mishnah:
According to Rabbi Shimon, a widow from marriage may sell outside of beis din for her maintenance, but may she also sell for her kesubah outside of beis din? The Rishonim disagree about this question: since the sale was permitted to her for maintenance, was it perhaps permitted to her for the kesubah as well?
In summary: In this Mishnah we learned the dispute between the first Tanna and Rabbi Shimon regarding the law of a widow who sells from the assets of the estate. According to the first Tanna, whether from betrothal or from marriage she sells outside of beis din, for the reason that a man does not want his wife to be degraded in beis din, provided that she sells in the presence of three people who are expert in appraisal. According to Rabbi Shimon, only the immediate need of maintenance permits a sale outside of beis din, and therefore a widow from betrothal, who has no maintenance and is selling only for her kesubah, sells only in beis din. And the Rishonim disagree as to whether, according to him, a widow from marriage sells outside of beis din for her kesubah as well.