The moral lessons also of this lady's novels , though clearly and impressively conveyed , are not offensively put forward , but spring incidentally from the circumstances of the story ; they are not forced upon the reader , but he is left to collect them ( though without any difficulty ) for himself
I think what the passage is trying to explain is that the moral lessons in Jane Austen’s novels are delivered with subtlety and grace. They are expressed clearly and powerfully, and never in a way that feels pushy or preachy. Instead of being imposed on the reader, the lessons in the novels happen naturally from the events and situations within the stories, and as a result, the reader can easily understand the intended message on their own.