Thich Nhat Hanh opens by teaching that genuine love is inseparable from genuine understanding — truly knowing another person's suffering, needs, and inner experience — arguing that without this understanding, what people often call love is closer to attachment or projection.

Core teaching he offers:

• Understanding requires deep, attentive presence with another person, genuinely perceiving their suffering and needs rather than projecting one's own assumptions or desires onto them
• He teaches that this kind of understanding must be actively cultivated through mindful attention, not assumed to arise automatically from romantic feeling or familiarity
• This foundational teaching sets the tone for the book's broader approach: love as a practice requiring ongoing mindful effort, not simply a spontaneous emotion to be passively experienced

This opening teaching establishes understanding as the necessary foundation the book's subsequent teachings on compassion and presence build upon.