Death in sims 3 3ds, there are not very many options. I have played sims 3 3ds and experimented with all types of death.
Starvation takes the longest for a sim to die. The first moon let you should get is "Hungry". This moodlet should lasty for about three sim hours untill the next moodlet should appear, "Very Hungry". This moodlet will let you know that your sim is very hungry and needs something to eat, this moodlet should last for 24 hours. After that moodlet you will get another one staying "Extreamly Hungry". Your sim will keep on making noises and will try to eat if you have free will on, this moodlet should last for another 24 hours. After that moodlet Your sim will die and the grave will be left behind for you to keep in storage or in your garden.
Fire is quite a quick death as you die quick. If an object is on fire your sims can stand in the middle of the fire. Your sim will get a moodlet saying on fire. If you put the sim out quick enough she/he can be saved but will be singed. But... if you don't your sim will die in 2 hours and will start yelling loud and will try to get out. After your sim dies to can put the grave in the garden. Like the other sims game on PC and PS3 the grim reeper will not come.
This death is the quickest out of all of them. First of all there must be a broken electronic in the house and a sim who isnt so fantastic at repairing objects. To make the death easier your sims should be very hungry and very tired. First you sim will get singed and will get up from being electricuted. After if you make you sim go back and do it again even through its still singed and tired your sim will die from electricution. This death is the quickest and can only take abou 1 hour (In game).