i'm trying to make the game a lot like the sims 2, i've done everything else except this and moved them into their sims 2 house. i know she apparently got abducted by aliens, but...

1. i don't have seasons.
2. sims usually come back after a few sim hours, bella never came back when she got abducted in the sims 2.

i know i could use testingcheatsenabled to delete her but i wanna eventually bring her back in case she's back in the sims 4 (i'm gonna copy that in ts3 as well) and i'm not sure you can bring them back after deleting them.

is there any other way to do it?

EDIT: is there a way to move sims into the family bin like you can in the sims 2? i was gonna try that but i'm not sure if you can.

You could kill her and store her grave in the mausoleum of the graveyard lot. That way she won't come out and haunt the world as a ghost but still remain in the Goth family tree.

Create a basement, lure her down there and delete the stairs.

if she's in the mausoleum, would i still be able to bring her back to life?

Yes. Depending on what EPs you have there are now several ways to bring a dead Sim back, but only if there's still a gravestone somewhere. From the base game there's the opportunity "Oh My Ghost!" that unlocks bringing dead Sims back as playable ghosts at the Science Lab, The Genie from Shwotime can bring back dead Sims, too, as does the Philosoper's Stone from Supernatural. Playable ghosts can then be turned human again by feeding them Ambrosia (level 10 cooking skill required + Death Fish and a Fruit of Life).
If all of that sounds too tedious you can speed that up with the DebugEnabler mod by NRaas Industries (nraas.wikispaces.com). It has both the options to resurrect a ghost and to create a plate of Ambrosia straight away. With the MasterController mod by NRaas you can also insta-kill a Sim and have the gravestone teleported right into the mausoleum. By that you can also avoid having Bella's thumbnail in family trees show up in the typical ghost colours and simply greyed out instead. Quite useful if you care about keeping up the illusion that she's simply gone, because it will also avoid any mourning from her family.

Keep in mind that Ambrosia also requires a very expensive recipe. (§12,000)

Here is more information on Ambrosia. It also requires a level 7 fishing skill to catch the Death Fish, and if you plan to grow the Fruit of Life, that requires a level 7 gardening skill.

http://sims.wikia.com/wiki/Ambrosia

Total Annihilation her!

That's an odd advice to someone who wants to bring her back eventually, because Total Annihilation is even more total than EA could ever manage. It would be as if Bella had never existed.

Oh haha, I missed that part.

what's this "total annihilation" thing in the game? i know what the real term means but what is it in the sims?

I intended not to explain (although most ppl here would know what it means). Most players here use an umbrella core mod that governs the game (mostly to regulate TS3 and streamlines everything, and gives us more control). We refuse to play TS3 without such mod. One of them is Awesomemod, the other is NRAAS. While Awesomemod is "all in one" mod (give or take), NRAAS is super modular and let you download only things you need. The umbrella in NRAAS falls under "MasterController" mod. As the name suggests, it governs how TS3 runs and offers players many controls. One of them is "Total Annihilation". It is designed for players to entirely get rid of one sim without trace (no memory, no evidence).

You can use it for "evil" intention, but mostly it is used to get rid of either problematic or really unintended sims, like they never existed at the first place. Their friends/relatives/enemies/co-workers will not remember them at all. One good example: your selfsim just ... knock up someone (or be knocked up by someone) without you even noticing until it is too late. "Kill" the baby? Or revert back a couple saves, losing some serious progress? I would just "Total Annihilate" the unintended baby sim. Nobody will ever be unhappy.

Yes you can, in Edit Town you can save a copy of a family, split it up or merge it with another family.

I had an elder sim that fell for another elder while on vacation and had her move into his house using master controller and set
her to being married to him. When my sims went on vacation they also visited grandma.

If Bella is not a member of your house add her to your household and go on vacation and just add her to an empty house or merge
her with another household. When you are ready to get her back go on vacation add her back to your household and bring her back.

That's a terrific idea. You'll need the MasterController mod for this, though, because you cannot split an active household while on vacation.