Multimodal Sentiment Analysis (MSA) integrates multiple modalities to better understand human emotions. However, existing methods often neglect heterogeneity among modal features, causing redundancy and inconsistencies. Additionally, the dynamic interplay between modalities is frequently ignored during fusion, limiting performance. To address these issues, we propose Reward-Guided Dynamic Fusion and Modality Decoupling (RDFD). RDFD includes two key components: (1) a feature decoupling module tha