In this research, we explore the role of interpersonal personalization in brand offerings in engendering the representations of ‘which dimension’ of brand personality (Aaker, 1997) and the subsequent effect on consumer attitude toward and connection with the brand (Fournier, 1998). Experiment 1 reveals that interpersonal personalization is different from customization with unique benefit in developing sincerity in brand personality. It demonstrates the positive effect of personalization on brand attitude through formulation of a sincere brand. Experiment 2 provides empirical evidence that personalization encouraging consumer’s involvement in the product design process allows consumer’s greater engagement with and investment towards the brand, which then manifests favorable brand attitude. The findings of this research offer insights on how brands can take advantage of personalization practice in their product or service offerings to engage consumers, and subsequently develop a close relationship with them. This research makes an important contribution to the brand personality literature through identifying a specific marketing approach (i.e., interpersonal personalization) as an effective strategy in developing a specific type of brand personality (i.e., sincerity). In sum, this research offers new view on how to manage close relationship with consumers, which is a significant practical implication for marketing managers.