In order to become betrothed (which is considered like complete marriage, except that a chuppah is needed before the couple begins to live together), the woman has to accept a valuable proffered by the groom and tell him that with this she agrees to become his bride. Let us look at some marginal cases.
If a woman on a cruise takes the betrothal money (a hundred zuz, about $5,000) from the man but immediately throws it overboard the ship, she is not betrothed. But we just said it!? – You might think that – since she would be obligated to return the money if she does not get married – she actually means to accept, but tests the husband in his anger management. So the teacher had to tell us that she is not betrothed, because she did not voice an agreement.
Another example: a man was drinking in a bar, and a woman came over and said, “Give me a drink.” He said, “If I do, will you become betrothed to me?” She replied, “Do pour a drink!” – Here too she is not betrothed, since she agreed to the drink, not to the marriage.
In addition to money or valuables, a man can betroth a woman with a document, where he writes, “With this document you become betrothed to me.” This is derived from other laws of sales, and it applies even if the paper on which it is written is not worth anything. Just like a bill of divorce, this document must be written with her in mind.
Finally, one can engage a woman by having relations with her – provided that he announces to the witnesses that this is his intent, and then secludes himself with her. This is derived from the words, “who cohabited with her husband
Art: Woman Drinking with Sleeping Soldier by Gerard Ter Borch