I've been suggested a kohen's daughter, but I'm no great Torah scholar. May I marry her, and do I have to remain a talmid chacham for the rest of my life?different viewsask your rav

He concludes that a chassan marrying a kohen's daughter should master at least one tractate -- even a small one is enough. What's required is grasp of the content, not knowing the text by heart. And he adds a reason for leniency: since this situation has become widespread, there's all the more reason to permit it. In his responsum he examines the source of this teaching and shows that it's derived only from the juxtaposition of verses, and therefore carries the weight of an "asmachta" rather than Torah law. What's meant, he explains, is an "ish zar" in the sense of an ignoramus; and when the husband is a talmid chacham, the match rises to its very best, since Torah outranks priesthood, and it's said that a mamzer talmid chacham takes precedence over an ignorant Kohen Gadol. He also defines who counts as a talmid chacham here leniently: since in our time kohanim don't eat terumah by Torah law anyway, a high level of scholarship isn't required -- knowing one tractate is enough. And to someone worried that even that is beyond him, he answers: here "Hashem protects the simple" applies -- since many people rely on this, it can be relied upon; besides, today even the kohanim themselves aren't considered kohanim with a fully verified lineage, so there's nothing to worry about.

“He only needs to know the content — he isn't required to know the text by heart.”

He brings the Shulchan Aruch's ruling that an am ha'aretz should not take a kohen's daughter and that such a marriage won't succeed, and shows how differently this is read. The Chana VeChisda holds that despite today's leniencies regarding kohanim, the rule still applies -- because of the danger in such a union. Others follow the Tzemach Tzedek instead: since kohanim today don't fulfill much of kehunah anyway, a full talmid chacham isn't required -- comfortable command of one masechta is enough. The Aruch HaShulchan shifts the discussion away from scholarship entirely: what's meant isn't an ignoramus, but someone careless in mitzvos, and one who takes care to observe carefully may take a kohen's daughter. The Steipler said it was enough if the chassan could work through a page of Gemara with Tosafos, and in one case said it was enough that the chassan even bothered to raise the Gemara's warning and ask the question.

“It's enough if the future chosson can work through a page of Gemara with Tosafos.”

He resolves the well-known halachic question of a kohen's daughter marrying a Yisrael by following the Tzemach Tzedek's responsum: the chassan should be proficient in one tractate -- then he's considered a talmid chacham, and the marriage isn't just permitted but blessed; he also adds the reasoning "since many rely on this, it's permitted." Asked whether the chassan must remain a talmid chacham for life, or else the shidduch shouldn't be made, the Rebbe answers that nowadays, and in these countries, it's enough that he knows one tractate -- even a small one -- by the time of the wedding. He gives the reasons directly: people marry mostly after the age of twenty; God-fearing kallahs today are fewer than before; and "many rely on this" applies far more broadly than in earlier generations. Per the Sages' guidance, the chassan of a bas kohen should increase and add to his learning, so as to come as close as he can, according to his ability, to the description of a talmid chacham. The practical measure depends on the time available: if there are several months before the wedding, he should try to finish all six sedarim of Mishnah beyond his regular study; if the wedding is closer, at least one or two sedarim; and at the very least, the small tractate Kallah. According to the Sages, a kohen's daughter should marry specifically a talmid chacham, so the chassan should add strength to his learning and his regular study sessions, so as to approach that title as much as possible. The Tzemach Tzedek rules that knowing even one tractate -- even the small tractate Kallah -- counts as a talmid chacham for this purpose. In practice: beyond his regular study, he should try to finish the whole Mishnah, all six sedarim, before the wedding if several months remain, or at least one or two sedarim if the wedding is near; and in any case go through tractate Kallah. Separately, the Rebbe notes to the chassan of a bas kohen that the whole Jewish people is called "bas kohen," since Hashem is called a Kohen and the Jews are His children, and he advises learning this tractate together with the maamar that explains the two meanings of the word "kallah."

“it's enough that he know one tractate by the time of the wedding.”