To intensify the expressiveness of the utterances in English, you can employ a variety of linguistic techniques, such as using stronger adjectives, adverbs, or adding emotional or descriptive phrases. Here are the enhanced versions of your sentences:
1. "You have been incredibly kind to me, and I deeply appreciate this. Your generosity has truly touched my heart."
2. "His position in the firm has significantly improved, rising far beyond what it was before. He's now in a much more influential and prominent role."
These modifications serve to amplify the emotional impact and descriptive quality of the original sentences.