killing a sim

Just select the sim and do nothing and let the time get faster and if he or she is trying to do a work just cancel it by pressing the triangle button...

Use the sim you want to kill then work and work until he or she starves don't let him or she eat anything.. If he or she doesn't want to work anymore just don't do anything eventually it will die by itself. After that if it dies you're going to have to change characters and go near the dead sim and mourn after that you'll get the death daisy.

i just created a four walled shelter with no doors and removed the bed from there and speeded up the time till the sim died then removed the walls and mourned and got the daisy that way

The easiest way would be making the sim harvest either clay, ore, obsidian, fine sad or pumice. Make small spaced confinement (four walls) and keep the sim in there, eventually, after holding down or pressing the fast forward button, it should die. After death, get a sim with good cooking skills, at least above 4, to mourn at the grave. The tears of the sim will water the grave and the death daisy will appear. Pick the death daisy and go to a craft bench (only do this if you have all of the ingredients though) and make the potion. Then go to the grave and choose the option 'Resurect'. The sim will come back to life.

how many times do you have to mourn to get the daisy

you have to mourn one time. The first time. Your sim will cry and cry and cry till it is friends with the dead sim.

Also to kill a sim you can surround it with walls it wil just shrug its shoulders till it dies. you can also surround it with firepits and if you can a deathrock in the place of one firepit. put the facilities nearby ie shower toilet bed so it just shrugs its shoulders in frustration. All it will be able to do is mourn. it will start coughing and it will grab its stomach and fall to the ground. then it is dead