I had always fancied that his manner to Cynthia was rather constrained, and that she on her side was inclined to be shy of him. 
Cynthia had many sides to her personality. 
mnli hypothesis: Cynthia had many sides to her personality.  premise: I had always fancied that his manner to Cynthia was rather constrained, and that she on her side was inclined to be shy of him. 