Compare and contrast Agnes and Emily?

Agnes becomes very close to David and advises him about numerous issues. She is described as calm, soothing, and tranquil.

It seemed to my imagination as if the portrait had grown womanly, and the original remained a child. Although her face was quite bright and happy, there was a tranquillity about it, and about her—a quiet, good, calm spirit—that I never have forgotten; that I shall never forget.

David immediately falls in love with Emily on his first visit to Yarmouth. She is sweet, caring, and compassionate..... completely innocent, though she does have a distinct fear of the ocean and drowning.