Well, for V4, first, your character must be male. Keep skill points low, and try to take bad care of your tamagotchi. If that sounds hard, try leaving it for an hour with full hearts in both hunger and happiness. When you come back, the hearts may be depleted by that time, perhaps even get a sick tamagotchi.
Cure that tamagotchi, then feed him once more with snacks and food to keep the hearts filled once more. Do it again.
My friend can vouch for this. Since she leaves her tama unattended in quite a long time, she has her tama die every so often or get a gozarutchi (male) or masktchi (female) consistently.
Also, from my previous tests, it's effective that way. It seems that gozarutchi is the universal tama you get when it's still alive despite the worst care possible. Debatchi, when worse care. Pyontitchi when bad care. This is for the male side.