Book Reports / 'The pear' by John Steinbeck - I need help about thesis statement [5]

Here is my thesis statement

" The book 'The pear' by John Steinbeck is a good example about characters. It shows different and unique characteristics. Kino is a very responsible character, Juana, who is more practical and the doctor, who is represent evil."

I asked my teacher is it ok. she told me it should be in one sentence. like " In the pearl, John Steinbeck ___attitude__ , because of ...___three reasons__"

what im trying to do now is to describe three characters, Kino Juana and doctor. I really don't know how to write them in one sentence. plz help me!