What is mean by yandere? Im totally clueless.....
Adding to what Enny said, Yanderes are also known to be capable of physically hurting their loved ones, and the extreme ones of being capable or having thoughts of killing their loved one in a jealous rage or from the thought of a breakup/separation. Perfect example of a Yandere is Chiharu from Fujisaki Kou's "Kemono" series. You can check it out here:
http://www.mangago.zone/read-manga/amaeta_kemono_no_shitsukekata/mi/mi_chapter-1/8/
Use google yourself sometimes
Why ya so cute yubin ε=ε=(ノ≧∇≦)ノ