So I will give you my tips how to finish it without any problems ;) (I am not native english speaker so sorry for any mistakes)
1. I recommend to wear a armour with 400+hp
2. I recommend to start the Dingy Jungle at the Default II (The lowest possible) - it will allow you to speedrun it and you will one-shoot almost every moob
3. If you can, use a mele weapon with "Anima Conduit" and "Soul Siphon" enchantments - it will give you an extra heal after you kill the monster. I have both enchantments and it was really easy. And it counts for this achievement ;)
if you have any question or need a help, my xbox gametag is - BajerKR