Personal experiences or things you have witnessed.
I am quite sure that she revealed her belief through her words. During the little dialogue scene where she runs on with what appears to be a conversation between her and Mrs Cobb, her words seem to give off a sense of discomfort.
I may be wrong here, but hopefully, you can see why I'm leaning towards this possibility! =)
Answer:
The city is portrayed as a challenge for Caroline to either use its advantages to mature or to succumb to its dangers.
Explanation:
Caroline Meeber (sister Carrie) is an eighteen year old lady who left her village in Wisconsin in search of a green pastures in Chicago. She was out to pursue her dream of wealth and fame.
The setting of passage 1 is a Chicago-bound train where Caroline, leaving home for the first time to stay with her sister, battles with her thoughts - how would life in the city be?
Nostalgic feelings of home are some quickly replaced with her expectations of city life - lights and sounds of a fast-paced city, moving cars, big houses and mansions, fame and affluence.
Even though Caroline was naive in thinking, her tastes and desires were certainly very high. She was also nervous and a bit fearful not knowing exactly what life in the city would offer her.
In which conversation?
In what story?
To highlight a character's (usually the protagonist's) personality, the introduction of a foil is used. In Shakespeare's 'Hamlet', Laertes is Hamlet's foil. They were childhood friends but have completely opposite traits and behaviors: Hamlet is verbal, he ponders, and is driven by passionate inaction, Laertes is physical, blusters, and is driven by passionate action.
In Act IV, scene V, we can see Laerts personality; he bursts and needs people to calm him down, whereas Hamlet would have stayed calm and think before acting.