In the growing digital market, brand loyalty has become a very important strategic goal of companies that want to be sustainable in the long run. Artificial Intelligence (AI), especially machine learning (ML) personalization approaches provide incredible opportunities to increase consumer engagement and stimulate repeat purchases. This work examines how AI based personalization services such as recommendation systems, predictive analytics, sentiment analysis, and dynamic pricing are affecting customer trust, satisfaction, and developing loyalty. The paper discusses how the learnings of consumer behavior theory, digital marketing models and interventions, strategies based on experiences in e-commerce can help create and generate custom experiences that appeal to personalized tastes, by synthesizing information based on the analysis of large amounts of data in the form of ML algorithms. The cause of loyalty has also been discussed in the research with terms relating to psychology of relevant, convenient and the emotional attachment and the challenge of personalization to boost them has been put to test. Meanwhile, issues about the privacy of data, bias algorithms, and consumer suspicions are importantly questioned. The study advances a theoretical model of relationships between the process of AI personalization and the intention of repeat purchase in digital environments with case-grounded findings of global marketplaces. Finally, this contribution points out that AI-enabled personalization is not merely a technological development but also a strategic tool providing sustainable brand loyalty, not only with considerable relevance to marketers and platform designers, but also to policy makers in the digital economy