The mishna says that a man can’t create a chazaka on his wife’s usufruct property. This seems to imply that if he brought a document attesting to ownership, he could prove purchase of the land. This is questioned from another mishna (regarding a different case) that a wife can claim she agreed to the sale only because she wanted to make her husband happy and can thus invalidate the document of sale. The gemara explains why that mishna is referring to a different case and would not be relevant here. The inference is also questioned by Ameimar’s statement that a man and woman who sell usufruct property did not do anything – the sale is invalid. 2 possible answers are given. Another question on the mishna itself is brought from Rav who says that a married women needs to protest (otherwise one can create a chazaka on her property). At first the gemara thinks this is referring to her husband and then needs to provide an answer. Rav Yosef explains that it could be referring to another man in which case his statement has nothing to do with our mishna.