Right at the very start of the novel, three of the boys go on a mission (after the first assembly) to find out whether the island actually is an island. And they find out that it is - and then come back and hold an assembly to tell the boys what they've found out.
Jack's keen to talk about the pigs and the hunting, but Ralph has to struggle to get his words out about rescue:
“That’s what I was going to say,” he went on, “when you all, all. . . .” He gazed at their intent faces. “The plane was shot down in flames. Nobody knows where we are. We may be here a long time.”
“But this is a good island. We–Jack, Simon and me– we climbed the mountain. It’s wizard. There’s food and drink, and–”
Ralph, in these first few chapters, is a good leader, I think: he knows to reassure the other boys, and he acts with real compassion in allaying their fears about the beast. He also manages Jack very well, to start with. And so he knows that he has to tell them what they want to hear:
“This is our island. It’s a good island. Until the grownups come to fetch us we’ll have fun.”
Fun and rescue. Ralph's two priorities. Yet - before much longer - the mulberry boy will mention the beast, starting the decline toward savagery which will weaken, and eventually crumble his reign.