This is possible in real life. Yandere is just an overdramaticized overdone trope version of incredibly toxic and abusive relationships.
Normally I wouldn't post in a thread like this since I avoid this trope like the plague because I find it absolutely repulsive, however I will say it would be possible IN A REAL LIFE SITUATION to get the person the hell away from you before they can physically harm you if you get the signs that he/she/they are being a horrible, nasty f*ck. If they stalk you or try to harm you, you can even get them arrested. No need to kill them and get yourself in trouble instead unless they straight up try to attack you, then it's self defense.
If this was an anime situation, however, I'd probably rather die because anime takes yanderes and makes them damn godmods for the most part with their "super strength of onesided love" garbage.
Sorry for my language and loss of a calm demeanor, I wanted to get my point across that I absolutely loathe this trope and it doesn't help that people romanticize yanderes even though it's a literal over exaggeration of abusive and controlling behaviors in a relationship.
Signature by KirbStomp!