What is the significance of Adele and Robert's conversation on the way back from the beach?

In this scene, Adele is warning Robert about misconceptions and preconceived notions. Robert is a notorious flirt, and Edna seems to be taking their flitation too seriously. Adele's warning is meant to warn Robert that although people know he's a flirt and prone to pay excessive attention to pretty women..... even married women, Edna might be taking him seriously. It seems that she believes although everyone else sees the innocence..... Edna is clueless.

Note, Adele's warning angers Robert, who claims his feelings are real. We'll soon find out.