Following the discovery of the magnificent pearl, their relationship begins to experience strain and tension. The potential wealth the pearl symbolizes brings out differing desires and priorities. Kino becomes obsessed with the idea of using the pearl to better their lives, particularly improving their son Coyotito's future. However, Juana remains cautious and hesitant about the pearl, sensing its dangerous and corrupting influence. This difference in perspective creates distance and conflict between them.
As Kino's obsession with the pearl intensifies, he becomes more impulsive and prone to anger, which puts a strain on their communication and intimacy. Juana senses the pearl's negative impact on Kino and their family, and she urges him to dispose of it before it brings them harm. Her fears prove to be justified when the pearl attracts envy and greed from others, leading to tragic consequences.
Despite their disagreements, Juana's love for Kino never wavers. She remains steadfast in her support for him, trying to reason with him and protect him from his own destructive desires. Juana's role as the voice of reason and caution serves as a contrast to Kino's increasingly irrational behavior.
Ultimately, their relationship endures the trials brought by the pearl but emerges scarred and changed. The loss of their innocence and the tragic events that unfold reveal the fragility of their unity and highlight the enduring strength of Juana's love and resilience in the face of adversity. Through the evolution of their relationship, John Steinbeck explores themes of materialism, greed, and the transformative power of unexpected wealth and its profound impact on individual character and familial bonds.