I don't know exactly who said it. It could have been a protagonist who came to this realization after going through a series of challenges and learning lessons about the futility of revenge.
One reason it stands out is the detailed world-building and the unexpected turns in the plot. Also, the character development is really well done, making you root for the protagonist throughout the story.
One characteristic is the beautiful art style. Manhwa often has very detailed and aesthetically pleasing illustrations that enhance the romantic mood. For example, the way the characters' eyes are drawn can convey a lot of emotions. Another is the variety of themes. They can range from high school romances like in 'True Beauty' to more fantastical ones like in 'Orange Marmalade' where there are vampires.
Romance manhwa novels often have beautiful art styles. The characters are usually drawn in an aesthetically pleasing way, which enhances the romantic atmosphere. For example, the detailed expressions of the characters can show their love, shyness, or longing vividly.
Well, a common feature of a typical romance manhwa is the focus on the emotional journey of the couple. There's usually lots of cute moments, maybe some obstacles they have to overcome together to strengthen their bond. Also, the art style tends to be very appealing, making the characters look charming and the settings dreamy.
I think the ideal protagonist for a manhwa romance could be someone who is brave in facing challenges and shows unwavering loyalty in love. They should have a unique background or story that adds depth to their character and makes the romance more compelling.