Is this the class I'm looking for?

[Xuluman]

I've played a lot of classes (up to level 10) but I'm always second-guessing myself and I can't get ahead.
Here is the list of things I need:
- Something to bailout when I screw up (Dying is NOT fun!)
|-> Heals preferred
- Very tanky
- Mobs die within 10-15 secs (when leveling)
- In PvP I'm a coward, need fear
- Being able to roflstomp when appropriate

I somewhat need a confirmation that this class is THE one I need to play. I'm already in doubt >.<

[Arev]

The closest thing to that would probably be a warlock. It is the only class with a spammable fear, has some self-healing, and has a pet that can tank some mobs for you.

If you really want to play a class that is very tanky, heal, roflstomp, and kill mobs in under 10 seconds when leveling, check out WoD :^)

[Botmaster5]

If you really want to play a class that is very tanky, heal, roflstomp, and kill mobs in under 10 seconds when leveling, check out WoD :^)

or roll a feral druid

[Bioness]

- Mobs die within 10-15 secs (when leveling)

Yeah, that isn't going to happen with any class without ooming yourself or using all your cooldowns.

[Thefilth]

Sounds more like a Mage imo.

[draxyl07]

- Something to bailout when I screw up (Dying is NOT fun!)
You don't have anything to bail out like a rogue's vanish or a hunter's feign death, but you do have a soulstone which you can cast on yourself which, should you die, allows you to resurrect yourself.

|-> Heals preferred
You have great self-healing through Siphon Life and Drain Life, as well as Health Funnel to keep your pet alive. Also health regen from armor buff.

- Very tanky
Voidwalker pet is great for tanking while soloing. Warlocks also have an armor buff that regens your health and gives you increased armor rating.

- Mobs die within 10-15 secs (when leveling)
Not really a possibility in vanilla for any class, if you're fighting equal-level mobs.

- In PvP I'm a coward, need fear
You've got fear, howl of terror, and death coil.

- Being able to roflstomp when appropriate
Depends how good you become at the class. Destruction can be deadly in the right hands in PvP.

[Numi]

I've played a lot of classes (up to level 10) but I'm always second-guessing myself and I can't get ahead.

- Mobs die within 10-15 secs (when leveling)

I somewhat need a confirmation that this class is THE one I need to play. I'm already in doubt >.<

Sadly, this isn't really something you'll be able to obtain in vanilla, but Warlocks are absolutely the class that can get you the closest to that, killing mobs in ~20 seconds, maintaining a 120-130 kill per hour rate for hours all the way from 20-60.

It's not easy and you'll die a lot trying to get those numbers before you learn it, but if that's what you want, stay with the warlock.