Torah Temima(Devarim 24:1.3): If she gives him something and she says I am betrothed to you because of what I gave you - then it is not a valid marriage (Kiddushin 4b). Rashi explains that she says to him “You are sanctified to me.” But Tosfos questions this since the language of kedusha doesn’t apply to a man since marriage doesn’t prohibit him to other women [See Kiddushin (2b), What is the connotation of the term kiddushin? It means that she is prohibited to the whole world like hekdash.] Therefore Tosfos explains that it means that she says to him, “I am sanctified to you.” However in my opinion the language of “kidashto” does not indicate that she is saying,” I am sanctified to you.” If it did mean that then the gemora should have said that she sanctified herself to him. But in general it is not clear where you learn that a woman can sanctify herself to him - since it is well known in many places in the Torah that in marriage the husband is the acquirer or purchaser! It would appear according to Kiddushin (9a), “How is a woman married through a document? The husband writes to the father, Your daughter is sanctified to me – then it is a valid marriage.” Thus we see explicitly that even though in commercial documents the seller writes, I am selling you my field, but here the husband is writing, Your daughter is sanctified to me - and the father doesn’t write, My daughter is sanctified to you. That is because in commercial documents the seller writes that he is selling his property because the Torah makes everything dependent on the seller. In contrast concerning marriage, it says, When a man will take a wife and thus the Torah makes marriage dependent on the husband.” Thus it is clear from this gemora that if the Torah hadn’t stated “when a man will take” the Torah would be understood and logic would support this - that in truth a woman could betroth herself to her husband because it would be equivalent to her selling herself to him – as it states, “And he will rule over you” and well as Tehilim (45), “Because he is your master...” In fact the Rashbam (Bava Basra 48b) explicitly writes that the betrothal of a woman is equivalent to the case of the seller selling himself to the purchaser. [see my explanation in ohs 6]. The normal way of acquisition is that the seller indicates what rights he is transferring to the seller. However since the Torah added in the case of marriage, “When a man acquire a wife” - the husband is the one who has to be described as acquiring rather than the seller writing that he is selling his rights to the purchaser. This point is the intent of the gemora before us. That if the wife says she is giving her rights to herself to him and she says that he now possesses the rights to her in the normal manner of commerce where the seller says to the purchaser, Go and establish possession – the marriage isn’t valid. Since the Torah states, “when he will acquire a wife,” that makes the validity of marriage totally dependent on his taking the initiative in what he says and his act of acquisition.