Eliza's new found self-respect has made her bolder and given her confidence. Self-respect is individual, and in Eliza's case we see her become proud of herself and her accomplishments. Thus, she sees herself in a whole new light and acts accordingly.....
One the other hand, respectability has to do with acceptance. Eliza wanted to be a lady, and she became one. She learned to be proper and because she did it so well..... was socially accepted. Her refinement, manners, and proper behavior put off Doolittle a bit because in the journey from flower girl to duchess, the spitfire (spirit) disappeared. He missed what she'd been.....