Sentence examples for not kidding from inspiring English sources

"not kidding" is correct and commonly used in written English.
It is typically used to emphasize that the statement being made is serious and not a joke or exaggeration. It can also be used to express disbelief or surprise. Example: "I am not kidding, I saw a monkey riding a bicycle on the street today!" The speaker is emphasizing that they are being serious and not joking about seeing a monkey riding a bicycle. Another example: "I am not kidding, I have been working on this project for weeks and it's still not done." The speaker is expressing frustration and disbelief about the length of time it has taken to complete the project.