"Gorilla, My Love" is a short story from the anthology of the same name by Toni Cade Bambara.
In the story, a young girl, Hazel, recounts her experiences with adults who change their minds about seemingly important things and directly or indirectly lie about their intentions. The film she pays for is changed without notice, and her beloved uncle is getting married instead of, as he said in jest, waiting for her to grow up. Her reaction is not uncommon but it shows a powerful and mature sense of honesty, right and wrong, and the consequences of lying.
I mean even gangsters in the movies say My word is my bond. So don't nobody get away with nothin far as I'm concerned.
(Bambara, "Gorilla, My Love," Google Books)
A useful thesis would concern Hazel's understanding of the concept of honesty; as a child, she takes things literally, while adults would not take a "white lie" as problematic. You could write, "Hazel's literal interpretation of the truth shows her immaturity, as adults often find white lies necessary to avoid hurt feelings."
Another good thesis might incorporate Hazel's refusal to consider that there are sometimes good reasons to be untruthful; it is possible that the film was damaged and the theater manager was trying to salvage his ticket sales with a spare print. You could write, "Honesty means something different to a child than it does to an adult."
Finally, Hazel's headstrong nature is born of her youth: children are often certain that they are right no matter the situation. You could write, "Hazel demands honest answers from adults, and she doesn't know or care that they have larger problems to deal with."
The story is short but there are a lot of interesting lines and themes to be drawn from it. Good luck!