With so many great classic romances in anime, it's easy for some amazing B-titles to get lost in the shuffle. Just because a title isn't trending (yet) doesn't mean that the writing isn't utterly swoon-worthy. Some anime romances are older and are largely forgotten by contemporary audiences, while others don't shine quite as bright compared to flashier new releases.
Source：https://www.cbr.com/anime-best-underrated-romance-series-ranked/
