He says this to reassure ralph that things will be ok. Simon is one of the most sensitive characters in the book and becomes aware of Ralph's worry. This is also an example of the books theme of herd mentality and social reliance since simon is aware of the effect his words and examples have on the others.
What is the primary purpose of these stage directions?
You should always look for the questions that may give off the idea that he/she is trying to persuade you. Also statements. For example, "My whole family loves to eat apples. You should try Granny Smith Apples they taste amazing!"
