A friend who’ll read your essay and circle the boring part is worth ten who say “looks good.”

Useful feedback has to risk your mood. Anybody can say it reads well, and that costs them nothing and tells you nothing, which is why it is the default response among people who like you. Somebody who marks the dull paragraph has accepted that you might be annoyed at them for an hour in exchange for your work being better. That trade is rarer than it sounds.

Ask for the specific thing rather than an opinion. Tell them to find the part where they stopped paying attention, and promise not to defend it. Then fix that paragraph before you fix anything else, and say thanks even if it stings.