Keep in mind that a thesis statement must present an argument or point of view about your topic, something that other people might disagree with but that you can support with evidence drawn from the text. Your topic of curiosity with regard to Nnedi Okorafor's novella Binti is a good one, and it could lead to some interesting and supportable thesis statements.

First, you might argue that curiosity actually drives the plot of Binti. If Binti were not curious about what it would be like to go to the university, she would never have left her family and started on her journey. Then there would have been no story. If the researchers had not been curious about the Meduse, they would not have stolen the chief's stinger, an event that leads to the attack on Binti's ship and her encounters with the Meduse. If Binti and Okwu had not been curious about each other and about Binti's otjize, they would never have become friends, and Binti might never have had the opportunity to serve as a mediator between the Meduse and the professors. So we can see that your potential thesis would be supportable through an interpretation of these scenes and others.

Second, as an alternate possibility, you might argue that curiosity stands at the heart of several of the characters. This is a variation on the previous thesis that would allow you to focus more on character development. You might talk, for instance, about how curiosity leads characters to take risks and to open up to one another, but you could also mention how curiosity sometimes leads to negative actions and conflicts between characters.