Ok, so I really need some help.

I did an interview earlier this week and met a mother and her son. Through the interview i got an idea of the mother's personality and I really think that she would be a royal pain for me if I took on her son.

My issue is that I'm not sure how to tell her that I don't want to care for her son without insulting either of them. I've had some really bad experiences before when I didn't listen to my gut and took on families that I thought might be trouble.

Can anyone help me out?