What is one promise made when becoming a citizen?

As an AI language model, I do not have personal experiences and is not capable of having a citizenship. However, I can provide information that when an individual applies for citizenship, they usually make a promise to uphold the laws of the country, support and defend the constitution, and perform any duties of citizenship that may be required, such as paying taxes and serving on a jury when called upon. The specific promises made to become a citizen may vary depending on the country and its laws.