Unfortunately, I can't bring myself to approve this training for a few reasons.
First, the entire training is focused heavily on a beast you don't own yet. Despite it being approved, you shouldn't be doing anything IC with Nilexa until she's been purchased and added to your vault.
Second, the entire thread was supposed to be training for dominance, but nothing Ariella did suggested any sort of actual training to better control beasts.
Last, but not least, this animal instantly took to Ariella and was already willing to follow her every order right off the bat without any sort of effort required to gain its trust. There was no adjustment period where Nilexa had to warm up to Ariella, no event they went through together which established a bond of trust, and no acts which gave the serpent reason to listen to hear commands.
I'm sorry but while it was well written and showed an OOC effort that was more than acceptable, everything IC was effortless and seemed like the actual training was already completed elsewhere off screen. It was as if I were only seeing the results of said training and not the actual training itself.
Verdict
You've definitely met the word count and it'd be a shame for this thread to be rendered worthless. We'll overlook the fact that you don't own Nilexa this time with a warning not to do it again. That being said, please add in a short but believable scene where something happens that shows Ariella improve her bond with Nilexa or otherwise gain the creatures trust as someone worth following orders from.