Now we'll talk about using certain items for kiddushin (betrothal). We'll talk about things that are usually in the Bet HaMikdash (Temple), or holy items. The Mishnah says that a Kohen (priest) uses a portion that he receives from a korban (offering) to get engaged to a woman, whether we're talking about the kodshei kodashim, holy offerings, or kodashim kalim, which are lesser holiness korbanot. The kodshei kodashim could only be eaten by kohanim in the courtyard of the Bet HaMikdash, while kodashim kalim could be eaten anywhere in Yerushalayim (Jerusalem), even by non-kohanim. So could he use these items to get engaged? We say no. The woman is not engaged. The Kohen doesn't own this. Even though he has permission to eat it, it's still mamon gavoha. It's the property of HaKadosh Baruch Hu (the Holy One, blessed is He). And Hashem just gives the Kohen, or the other person who's allowed to eat it, permission to eat it. But it's not theirs to use as kiddushin.
And in Ma'aser Sheni, Ma'aser Sheni is the portion of produce that a person has to remove, and he has to take it to Yerushalayim and eat it over there, or he could redeem it. He could podeh, redeem the produce that he has for money, if it's too burdensome to bring it all the way to Jerusalem, and then take the money to Jerusalem, add a certain amount to it, a chomesh, add one-fifth to it, and spend that money in Yerushalayim, buying food over there with it. When you take that money and get engaged to a woman, we say bein b'shogeg, bein b'mezid, whether he did it knowingly or unknowingly, whether or not the woman knew that it was Ma'aser Sheni, lo kidesh, she's not engaged; the engagement does not take effect. The same as with korbanot, according to this opinion, which is divrei (words of) Rabbi Meir. The Ma'aser Sheni is like a korban; it's owned by Hashem. It has permission to use it in a certain way, but if he doesn't own it, he can't get engaged with it. Therefore, eina mekudeshet (she is not betrothed).
Rabbi Yehuda omer (says): b'shogeg lo kidesh, b'mezid kidesh. Says Rabbi Yehuda, if she accepted it without understanding that it was Ma'aser Sheni, and without understanding all the restrictions that come with this food, then we say eina mekudeshet, she's not engaged. Ma'aser Sheni comes with a lot of different rules, and we make the assumption that unless she knew that it was Ma'aser Sheni, she is not engaged. Kiddushin was based on a mistake, and therefore, it's not valid. But if she knew that it was Ma'aser Sheni, and she got engaged with it anyway, we're making the assumption that she agreed to all of the restrictions that came with it. So what we can understand here from Rabbi Yehuda is that he says a person does own Ma'aser Sheni, and he can get engaged with it, but he has to make it clear to the woman he's getting engaged to that it is Ma'aser Sheni. So the kiddushin is valid.
We'll now have a machloket (dispute) about whether a man is allowed to get engaged to a woman with property of the Bet HaMikdash, Hekdesh (consecrated property). One is not allowed to use Hekdesh for private uses whatsoever. Uvehekdesh, let's say a man gets engaged to a woman with Hekdesh, which is property of the Bet HaMikdash, something that maybe someone donated to the Bet HaMikdash and he has with him, or he's using property of the Bet HaMikdash. We say b'mezid kidesh: if he gave it to her knowingly, they both knew what was going on, then she is engaged, even though a person is not allowed to use Hekdesh for his own uses. If he uses it on purpose, the item loses its holiness, and it doesn't belong to the Bet HaMikdash anymore. So now it's an ordinary item, and he uses it to get engaged to this woman. At the same time, he does have to repay the Bet HaMikdash, and he would receive malkot, he would receive lashes for violating and using the property of the Bet HaMikdash.
Uv'shogeg, but if he gave it to her unknowingly, they didn't realize that they were dealing with Hekdesh over here, lo kidesh, we say that she's not engaged. We assume that if they knew what was going on, if they knew that they were using Hekdesh over here, they wouldn't be okay with it, and therefore the whole thing is null and void. The Kiddushin was based on a mistake, and therefore is not valid, divrei Rabbi Meir. This is the opinion of Rabbi Meir. If they did b'shogeg, if he used Hekdesh in a mistaken way, he would have to repay the value of the item, plus a fine, and he also has to bring an asham offering in the Bet HaMikdash. This is the opinion of Rabbi Meir.
Rabbi Yehuda flips it. Rabbi Yehuda says that if he gave the item to her without knowing that it was Hekdesh, she's engaged. The item loses its holiness and becomes an ordinary object. Rabbi Yehuda would say that people don't really care; people wouldn't have anything against using a holy item of the Bet HaMikdash to get engaged. Maybe they'll even think it has some religious significance, and therefore they would all have agreed to have it done in that way. There's no halachic problem having it done like that. But if he gave it to her knowingly, he knew that it was Hekdesh, we say that she is not engaged, because according to the opinion of Rabbi Yehuda, you could only remove an object of Hekdesh from its sanctity if you didn't know you were doing it. In other words, he understands that using the property of the Bet HaMikdash can only be done when it's being done. But if you tried to use the property of the Bet HaMikdash on purpose, you don't take ownership of it, you don't cause it to lose its sanctity, it's not yours to use as kiddushin; it's still property of the Bet HaMikdash, so it cannot be used as kiddushin.