She plans to seduce him and shatter that innocence.
“She imagined that the two of them walked on the place until they came to the storage barn beyond the two back fields and there, she imagined, that things came to such a pass that she very easily seduced him and that then, of course, she had to reckon with his remorse. True genius can get an idea across even to an inferior mind. She imagined that she took his remorse in hand and changed it into a deep understanding of life. She took all his same away and turned it into something useful” (page 2533).
This quote shows that she thinks he is an innocent and she plans to seduce him and show him how the world works. She thinks that she is more experienced and knowledgeable than he is. She also finds herself attracted to him because they are similar people. He had told Mrs. Hopewell the night before that “I got this heart condition. I may not live long” (page 2529). Joy has the same