Saying no
I appreciate that you ask. I need to prioritize other commitments, so I have to say no.
Thank you very much for the request. I appreciate it. At the moment I have a lot on my plate. Due to limited time I will not be able to do good work on the project you propose.
I do not feel comfortable doing that. I have to decline.
I am sorry. I cannot do that for you.
I cannot do that. What I can do is
Currently, I am not able to help with that.
Thank you for thinking of me.
At that time I am not available. I’m sorry.
Thank you for the invitation.
I believe I do not have skills to do this well. I see two possibilities:
1. I can recommend another person, who may be able to help you.
2. If you accept that I need extra time to learn more about this, I will be happy to try to help.
Thank you. I feel honoured that you think of me in this regard.
I need to know more. May I please ask you these 3 questions:
Sources of inspiration
https://chat.openai.com/
https://greatergood.berkeley.edu/article/item/21_ways_to_give_good_no
https://hbr.org/2020/09/learn-when-to-say-no
https://hbr.org/2015/12/how-to-say-no-to-taking-on-more-work
https://psychcentral.com/lib/learning-to-say-no