Read this - but of course, you are free to refuse

To double your chances of someone agreeing to your request just add “but you are free” (BYAF) to the end of your sentence. It tells the person you are asking that they are free to refuse the request. Christopher Carpenter looked at 42 studies on the BYAF technique’s effectiveness and found that it worked regardless of the type of request. The technique is only less effective when the person doesn’t answer you immediately and instead has time to go and think about the request....
https://www.researchgate.net/blog/post/read-this-but-of-course-you-are-free-to-refuse