This chapter explores the evolving role of customer satisfaction, experience, loyalty, and trust in the context of sustainable marketing. As businesses shift from product-centric to human-centered strategies, the chapter examines how organizations can foster meaningful, long-term relationships with stakeholders by integrating sustainability into every aspect of the customer journey. It discusses the transition from traditional satisfaction models to holistic customer experience management, the distinction between attitudinal and behavioral loyalty, and the foundational importance of trust. The chapter introduces frameworks such as the Trustworthiness Equation and Human-to-Human (H2H) marketing, emphasizing empathy, authenticity, and emotional intelligence. Through real-world examples and practical tools, it demonstrates how managing human relationships is essential for delivering sustainable value and achieving organizational growth in an era defined by heightened social and environmental consciousness.