How to refuse without offending the leader?

He should be interested in your leadership. If you refuse him, you must give him enough face. Otherwise, if you are so cold-faced, how can people behave in the future? Well, you can talk to him in advance, and you must win his approval. I believe he will give up if he understands what you mean, otherwise he can't lead this position. He will be embarrassed to call you so often again. Besides, this is your relationship. You can't offend him, or you will be numb in the future. Tired of it, besides, you are a girl who can do this job, which proves that your brain is not bad. You should improvise and keep a certain distance from him. If he is really struggling, you can tell him that you have a boyfriend and make him respect himself. He'll stop.