>>15393927The appeal of the Yandere is that they can be mentally unstable. (The concept of Yanderes going on murdering sprees is simply popularized by Mirai Nikki) Yandere's are girl's who have a love for their target that borders obsession, and usually do somewhat odd/crazy things for their love, and are usually extremely possessive of them.
However, Yanderes are mentally off and obsessed over 'you'. You have their love just by being yourself, and they'll love you for it, and want to spend every minute with you, and hope that you wish to with them.
Also another thing is that in the brain love and fear are very close to each other, so it could also be something from that.
Tl:Dr: Yandere is best dere.