According to Aristotle, "to love is to want the good of the other as another", that is, to do everything possible to help him achieve, to be loved, his maximum perfection, the development of all his latent potentialities.
Love, when it seeks the perfection of the person it loves, all it wants is the good of it, which means "the perfect in its kind", and consequently its happiness.
That is why to "love", "seek the good of the other", "achieve perfection"; it is necessary to know the truth "conformity of thought or idea with the reality of things"; so that, with freedom, man is capable of addressing good.
Plato only says: "... Beauty, which exists eternally, is neither born nor dies, nor is it now beautiful and then not, nor beautiful here and ugly in another place, nor beautiful for these, and ugly for those. nor represent this beauty as it is represented, for example, a face or hands, or something else belonging to the body, neither as a discourse or as a science, but exists eternally by itself and with itself ... "
This is how the impossibility of the person to be able to love evil properly becomes evident. It is also true that reason can make some bad judgment; and it is for this reason that man with his freedom can decide to choose or address "that which the intellect presents him as good" even though there is another greater good.
On the other hand, it is important to emphasize that love yearns to possess a good with the intention that it will always last. "It is necessary to know well what it is to love the beautiful, it is to wish to appropriate it and always possess it, to be happy." Man aspires to the production of beauty through the body; and as beauty is the object of being loved, it is wanted to perpetuate without interruption, because "love is nothing other than the very desire for immortality".
The only immortality possible to man with respect to the body; it is produced by the birth of children, by the succession and substitution of an old being by a young person. On the other hand, the beauty that man seeks according to the spirit or the soul, has to do with perpetuating wisdom (works of thought, art, poetry and inventions of all kinds), which ensures immortality far superior to the first.
To conclude, it is not enough just to "want the good of the other", but that of oneself. And it is precisely the fact of "loving" the other, brings with it a desire to perfect oneself, because thus, by donating us, we will constitute "a good" for it.