Whilst conversational AI offers an ample amount of potential for the healthcare sector, many current systems fall short in the areas of emotional intelligence, fairness, and politeness—qualities that are essential in building patients’ trust. This disparity undercuts the promise of digital health solutions and frequently causes worry among users. This study addresses the difficulty of integrating these ethical guidelines into practice by creating and assessing LunaAI, an innovative chatbot for healthcare assistance. Utilizing user-centered design concepts and a thorough literature review as a foundation, we built sophisticated conversational scenarios that addressed hostile user behaviour. These concepts were developed into a functional prototype using Google’s Gemini API and a mobile-focused Progressive Web App (PWA) created with React, Vite, and Firebase. To ensure its efficacy, we conducted preliminary testing with a small individual group, analyzing their responses with established frameworks such as the Godspeed Questionnaire. Furthermore, a comparative analysis was undertaken between LunaAI’s personalized responses and the initial outputs of an uncustomized Large Language Model (LLM). The results demonstrated that LunaAI has made significant improvements in multiple key areas; users rated it 4.7/5 for politeness and 4.9/5 for fairness. These findings have substantial effects on the future development of human-computer interaction, particularly in sensitive domains like healthcare, and emphasize the significance of purposeful, ethical conversational design.