Some people dread providing honest or frank feedback to people they like or know well.
Might be useful (for example) to say to a friend, “I really need feedback on chapter 2 for an idea I have for a future project. When you have time, could you do a quick read of that chapter and let me know what you think?”
If they love it, they might read more, including chapter 1. If they are bored or busy, you might nonetheless get useful insights from whatever they say.