Jonathan crane is many things, ex professor of psychology, a chemical terrorist, a member of the world's gallery, and the newest thing you can add to his belt, a yandere tamer
though he's only achieved to domesticate one so far, he's also had experiences with other yandere's, so he believes he knows enough to be an expert, so he decided to sit down and write a book
Step one, find the route of the yandere tendencies
from Jonathan's own experience with the many yandere's in his life, the most common root of the Tendencies is childhood
take for example Harley, a childhood of emotional abandonment led to her spiraling into the arms of the Joker, or for another example take his own partner jervis who due to a combination of caring but misguided parents and school bullying became the man he is today
now that one has found the root of your yandere's issues we now turn
to step two, make sure they know they don't have to do anything drastic to make you stay
if you suspect do yandere suspects you want to leave them and is planning something drastic it is best to sit them down and tell them the best way to make you stay is to communicate the issue they think you have with them and to talk it out
Jonathan himself had to figure to do this the hard way after the third time jervis locked him in his lab
step 3, assure your yandere that no one can ever take you away from them
if you suspect that you're Yonder suspect that someone's trying to take you away from them like you did with the other step sit them down and reassure them that no one can or will, you may need to do this repeatedly for to set into their minds
for example Jonathan had to tell jervis that no the barista at his favorite Cafe wasn't trying to get into his pants like five times
and finally enjoy your new life with your yandere partner
now that you have made sure that your new partner won't go out on a murder spree or lock you in their basement for the rest of your lives, you can now live a happy life partnered with a psycho that you can sick on people you don't like
and thus Jonathan finishes his book and probably puts it with the rest of the books he's written but legally can't publish because he's a criminal, and he gets up to go back to bed with his psycho boyfriend