1) KIDUSHIN PERFORMED WITH "MA'ASER SHENI"
QUESTION: The Mishnah (52b) quotes Rebbi Meir who maintains that when a man is Mekadesh a woman with fruits of Ma'aser Sheni, the Kidushin does not take effect. The Gemara teaches that Rebbi Meir's source is the verse, "v'Chol Ma'asar ha'Aretz... la'Hashem Hu" -- "and all Ma'aser of the land... shall be for Hash-m" (Vayikra 27:30).
RASHI on the Mishnah (52b, DH b'Ma'aser Sheni) explains that Rebbi Meir maintains that Ma'aser Sheni is "Mamon Gavo'ah" (as the Gemara on 54b states explicitly). This implies that Ma'aser Sheni is not the property of the person who separated the Ma'aser, but it belongs completely to Hekdesh. If the Ma'aser belongs completely to Hekdesh, why does the Gemara teach that Ma'aser Sheni may not be used for Kidushin because of the specific rule derived from the verse, "la'Hashem" -- "'la'Hashem' v'Lo l'Kadesh Bo Ishah"? The Gemara should mention a more general, all-encompassing rule such as "'la'Hashem' v'Lo Mamon Hedyot," which also teaches that it cannot be used for Kidushin since it is not considered the property of the bearer.
ANSWER: RABEINU CHAIM HA'LEVI (cited by the CHIDUSHEI HA'GRIZ in Zevachim 6a) makes a similar observation in the words of the RAMBAM in reference to the Gemara here. The Rambam (Hilchos Ishus 5:4) writes that if a man "was Mekadesh a woman with Ma'aser Sheni, whether by accident or on purpose, she is not Mekudeshes, because he is not to use it for any of his personal purposes until it has been redeemed, as the verse says, 'la'Hashem Hu'." Why does the Rambam not write that the reason is that the Ma'aser does not belong to the man until he redeems it? The wording of the Rambam implies that there is a specific prohibition against using Ma'aser Sheni for one's personal needs.
Rabeinu Chaim concludes that Ma'aser Sheni indeed belongs to the owner and, monetarily, it is considered his property. The verse of "la'Hashem" merely limits the owner's ability to use it and prevents him from using it in any way that he wants. It is his property only to perform with it the Mitzvah of eating Ma'aser Sheni. He may not do anything else with it.
Rabeinu Chaim explains that the status of ownership of Ma'aser Sheni has a practical difference in the case of Yerushah, inheritance. When a man dies with fruits of Ma'aser Sheni in his possession, do his children inherit his Ma'aser Sheni? If Ma'aser Sheni is not considered his property at all, his children should not inherit it. If it is considered his property (but with regulations about how he may use it), his children should inherit it.
According to Rabeinu Chaim, the wording of the Gemara here is very precise. The exclusion derived from the verse is not an exclusion in the ownership of the Ma'aser but in the type of usage that is permitted. That is why the Gemara says that it is "'la'Hashem' and not l'Kadesh Bo Ishah." The Gemara refers to the type of usage that is permitted and not to who owns the Ma'aser Sheni.
2) "SHIGEGAS MA'ASER" ACCORDING TO REBBI MEIR AND "SHIGEGAS HEKDESH" ACCORDING TO REBBI YEHUDAH
OPINIONS: Rebbi Meir in the Mishnah (52b) states that when a man is Mekadesh a woman with fruits of Ma'aser Sheni, the Kidushin does not take effect, regardless of whether he gave her the fruits b'Shogeg (unaware that they were fruits of Ma'aser Sheni) or whether he gave her the fruits b'Mezid (aware that they were fruits of Ma'aser Sheni). Rebbi Yehudah disagrees and says that if he gave her the fruits b'Shogeg, the Kidushin does not take effect, but if he gave them b'Mezid, the Kidushin does take effect.
In the next case of the Mishnah, in which a man is Mekadesh a woman with an object of Hekdesh, Rebbi Meir rules that the Kidushin takes effect if he gave her the Hekdesh b'Mezid, but it does not take effect if he gave it to her b'Shogeg. The Gemara asks what the difference is between the respective rulings of Rebbi Meir and Rebbi Yehudah in each case (Kidushin with Ma'aser Sheni and Kidushin with Hekdesh).
Rebbi Yakov quotes Rebbi Yochanan who answers that "in one case [of Shogeg], the woman does not want it, and in the other case [of Shogeg], neither [the man nor the woman] wants it." Rebbi Yakov says that Rebbi Yochanan's statement may be interpreted to mean that in the case of "Shigegas Ma'aser," neither the man nor the woman would have wanted the Kidushin to take effect had they known that the fruits were Ma'aser Sheni. The woman does not want to receive fruits of Ma'aser Sheni because she does not want the inconvenience of having to bring the fruits to Yerushalayim to eat. The man does not want to give fruits of Ma'aser Sheni because he does not want "an accident to happen on the way" while the woman brings the fruits to Yerushalayim.
RASHI (DH Mishum Onsa d'Orcha) gives two explanations for why the man would not have wanted the Kidushin to take effect had he known that the fruits were Ma'aser Sheni. In his first explanation, Rashi writes that since the fruits are not worth a Perutah except within Yerushalayim, he remains responsible for them until she arrives in Yerushalayim. Since a woman is susceptible to accidents, it is likely that something will happen to the fruits and he will be liable to pay for them.
In his second explanation, Rashi writes that even if the man accepts no responsibility for the fruits, he still would not have wanted to give her Ma'aser Sheni for Kidushin, because if she loses them (or some other accident occurs) she will be upset at him that he was Mekadesh her with something of no value.
The Rishonim differ as to when the Kidushin actually takes place according to the first explanation in Rashi.
(a) TOSFOS maintains that since the fruit or money of Ma'aser Sheni has value only in Yerushalayim, the Kidushin takes effect only when the woman reaches Yerushalayim and can use the Ma'aser Sheni there.
(b) The RITVA maintains that since, in Yerushalayim, the money of Ma'aser Sheni has the value of a Perutah, the Ma'aser Sheni is considered to have that value even before it enters Yerushalayim. Therefore, the Kidushin takes effect immediately, when the man gives her the Ma'aser Sheni for Kidushin.
Based on these two different ways of understanding Rashi's explanation, the man's acceptance of responsibility (Kabalas Achrayus) may be understood in two different ways.
According to Tosfos, Kabalas Achrayus means simply that since the Kidushin has not yet taken effect, if the money is lost before it is brought into Yerushalayim the man will have to replace it with other money of Kidushin. If he does not replace it with other money, the Kidushin cannot take effect, because at the time that it should have taken effect there was no Kesef of Kidushin present.
In contrast, according to the Ritva, the Kabalas Achrayus refers to an added obligation which the man accepted upon himself. He voluntarily accepted this obligation in order for the woman to have peace of mind and not worry about her inability to use the money she receives from the man.