The speaker's Heart was broken by love that it had not sought out in England. The south wind brought longing, the east wind despair, the west wind pathos, and the north wind fear. His Heart feared the hurt that the girl might bring, and thus went mad.
The Heart laughs and asks the speaker why he called him mad to run away from so young a girl. How could she have mated with someone so wild and old, it wonders. The speaker answers that he found her also wild, and tells the Heart that it fabricates lies. The Heart tells the speaker to say whatever he likes, now that the girl can no longer hear him. Now she will no longer mistake childish gratitude for love; now she will choose a young man for his wildness.
The capitalization of the word "Heart" is the speaker's own. In dialogue with his heart, he attempts to isolate it, to hold it apart from himself to save himself from despair. The dialogue between the speaker and his heart is Classical in character (many philosophical debates were framed in this way), but it is unclear who is the teacher and who is the student.