Throughout the poem, Aengus refers to the "heart of a woman" as something that is both fragile and powerful. He says that it is "like a bird in a bush" and that it is "like a flame in a lamp." These metaphors suggest that the heart of a woman is something that is both beautiful and dangerous. It is something that can bring great joy, but it can also cause great pain.
Aengus eventually finds his ideal lover, and he is able to possess her heart. However, he knows that this happiness will not last forever. He says that "I shall grow old and weary, / But I shall not forget / The heart of a woman." This suggests that the heart of a woman is something that is worth cherishing, even if it is only for a short time.
The "heart of a woman" is a central theme in the poem "The Song of Wandering Aengus." It is a symbol of love, longing, and desire. It is something that is both fragile and powerful, and it is something that is worth cherishing.