Hilchos Ishus 5:21
Let’s say that a woman tells a man that she’ll be consecrated to him if he gives a gift to a third party. If he says that she is consecrated to him by virtue of the gift that he gave at her request, then marriage is effected. Even though she didn’t receive anything from him, she derived benefit from her wishes being carried out and the third party derived benefit because of her. Similarly, if the woman told the man to give a dinar (a denomination of coin) to a certain person as a gift and she will be consecrated to that person, marriage is effected provided that the recipient tells her that she is consecrated to him through the pleasure she received from him accepting the dinar at her request.
Hilchos Ishus 5:22
Similarly, if a man tells a woman to accept a dinar as a gift and be consecrated to a third party, marriage is effected so long as that other person tells her that she is consecrated to him on the basis of the benefit she received from him. This is effective even though he didn’t personally give her anything. Let’s say a woman tells a man to accept a dinar as a gift and she will be consecrated to him. He accepts the coin and tells her that she is consecrated to him through the pleasure she derived by him accepting her gift. If he is an important person, marriage is effected because she is pleased that she was able to benefit him. This pleasure is sufficient to effect marriage.