A yandere girl in manhwa is often extremely possessive and obsessive about the person she likes. She can go to extreme lengths to keep them close, sometimes even resorting to violence or manipulation.
In manhwa, yandere boys typically have a dual personality. They might seem normal on the surface but go to great lengths to keep the object of their affection close. Their actions can range from overly protective to outright violent when they feel threatened.
I'd recommend 'Twisted Love'. The yandere male lead's actions keep you on the edge of your seat. The plot has lots of twists and turns that make it stand out. The way the relationship develops is quite unique.
The 'Desire Wife' manhwa mainly focuses on the protagonist's pursuit of love and facing various obstacles. It has twists and turns that keep you engaged.
The story in 'The Sedative Wife' manhwa could be anything from a thriller where the use of sedatives leads to a dangerous conspiracy to a heartfelt drama about a wife's struggle. It's quite ambiguous until you delve into the actual plot.