Tristan presents love as an overwhelming force that radically alters a person’s personality and values. It effectively makes somebody a different person in that it reorients their loyalties and their commitments and changes the range of their emotions. Under the spell of love, lovers previously characterized by their honor and virtuosity become willing to risk death and disgrace to be with their lover. Nevertheless, the story also exalts love, depicting it as a transcendent experience that justifies practically any suffering. This duality is a staple of the courtly love tradition.

Although the story depicts love similarly regardless of its origins—Rivalin and Blancheflor, King Mark, and Isolde of the White Hands all find their lives upended by the emotion—the love potion and its effects crystallize the story’s portrayal. Under the potion’s influence, Isolde immediately transforms from somebody who hates Tristan for having killed her uncle to somebody who is passionately devoted to Tristan. Similarly, Tristan transforms from somebody characterized by his deep devotion and loyalty to Mark to somebody who betrays Mark by sleeping with his fiancée. Love is such a powerful force that it destroys the longest and most strongly held loyalties and ideas of honor and replaces them with new needs and loyalties.