Well, there are a number of highly revealing statements that Silas makes in this short chapter, which is, in a sense, designed to show how far his character has grown and developed. Let us remember that in this chapter Silas revisits for the first time his old home in Lantern Yard, which was of course the site of so much sadness, pain and betrayal for him. When he goes and finds no evidence whatsoever of his former chapel, which has now been turned into a factory, he is forced to accept that he will never know the truth of precisely what happened. However, he says that this is not important to him any more. Note the reasoning he has for this:
Since the time the child was sent to me and I've come to love her as myself, I've had light enough to trusten by; and, now she says she'll never leave me, I think I shall trusten till I die.
We see the full movement of Silas Marner from being a rejected and alienated individual, without attachments in his community, to depending on another person so completely and fully that he is able to have faith in humanity once more. Eppie's decision to never leave her father has cemented this transformation, giving him "light enough" to trust in others and to have faith once more.