You can set your favorite reviews to be always visible at top part of the Reviews Widget in product pages by setting them as Featured reviews.
Featured reviews badge will appear on the Reviews widget if a review is set as Featured review.
You can also set the display order of Featured reviews if you set more than one Featured reviews for a product.
Learn more about Featured reviews configuration here.
You have to set the default sorting option of the Reviews Widget to Featured to use Featured reviews feature.