His speech and behavior display the refinements of a well-educated gentleman.

refinements 是名词 refinement 的复数形式。refinement 由动词 refine（精炼、使优雅）加后缀 -ment 构成，表示"精炼、优雅"的状态或品质。在这里指"教养、优雅的举止"。 refinements of a well-educated gentleman 整体意思是"受过良好教育的绅士所具备的优雅举止和教养"。