When you’re about to ask for something, be gracious and give control to the other one to say “No” without feeling guilt for saying so.
That way you’ll save both of you of fake “Yes” and “I’ll think about it”.
A couple of ways to do this:
Feel free to say no, but it’d be amazing if you could. [Here comes your ask].
It’s totally ok to say no, and here I have something to ask [your ask].
We’re fine if you say no, but I need your help with something important to me.