If the boy you love witnesses you committing murder, he could never love you, and the game would be over. If you truly want her to suffer, convince every other girl in school to bully her until she commits suicide and saves you the trouble. If you don't want to get any blood on your hands, you can use social sabotage to get rid of a girl frame her for one of your crimes, get her expelled from school, or ruin her reputation.
If you don't dispose of corpses, clean up blood, and destroy evidence, then the police might be able to link you to a murder and arrest you. You can use stealth to kill your target without any witnesses, stage an accident that leaves no evidence, or just slaughter anyone who gets in your way. The gameplay is similar to the Hitman series you are put into a large environment filled with many NPCs, and you must track down a specific target and eliminate them. Debug builds are available for testing purposes. Yandere Simulator is a stealth game about stalking a boy and secretly eliminating any girl who seems interested in him, while maintaining the image of an innocent schoolgirl.