Online dating has become a social infrastructure, with over one-third of marriages originating from digital platforms. Despite its significance, our understanding of how users form impressions and make matching decisions remains limited. This study addresses this gap by proposing and testing a "Two-Pathway Heuristic Model" of impression formation, arguing that users evaluate profiles via two parallel pathways: an immediate, affective assessment of facial attractiveness and a more inferential assessment of social attractiveness (or vibe). Using data from 10,619 users on a major heterosexual dating platform in South Korea, we leverage a Large Multimodal Model (LMM) to quantify facial attractiveness and social attractiveness, decomposing the latter its key components: social, economic, and cultural capital. Through econometric analyses, we examine both the independent and the interaction effects of these two pathways on matching success. Our findings reveal that while both facial attractiveness and social attractiveness are strong predictors of matching success, effect of facial attractiveness is particularly decisive for male profiles. Furthermore, our analysis uncovers significant negative interaction effects, suggesting that when a user's facial attractiveness is already very high, adding strong signals of social or cultural capital yields diminishing returns. These results offer novel insights the non-linear patterns of impression formation in digital environments and provide practical implications both users and platform designers, suggesting a need for interfaces that showcase multi-dimensional aspects identity beyond physical appearance.