Is it possible to choose to love someone?
Choice regards the means, and is chosen for the sake of an end. So if we choose to love someone, that would have to be for the sake of some end. But normally if you do something for someone, but order it to something else, that would not count as love. Thus if you give someone alms in order to make them like you, that does not seem to be true love. But then we could respond by saying that we can choose to give them alms for their own good, and this would be love.
But why did we seek their good? Either we already desired it, and thus we already loved before we made a choice, or we did not desire it in advance, but chose to seek it. In the latter case, there must have been some end for the sake of which we chose to seek their good. If this end is extrinsic, then once again this does not seem to be real love — we sought their good, but only because it was useful for something else. If the end is not extrinsic, for example God, who as the Supreme Good is not extrinsic to any good, then this choice presupposes that we already loved God.
In this way it follows that choosing to love always presupposes at least a love of the ultimate end. But what if we do not already love the ultimate end? How can we obtain love, given that no act that we make can be real love, without already having this love?
We can however choose to dispose our lives to love, namely to act in the way one would act who loves. According to St. Thomas, in such a case a person will always receive true love. This happens, he says, because of the generosity of God, who gives form to every disposed matter.