Good luck on all of this, and thanks for sharing your story with us!In her case she has no assets such as a business, property etc, therefore in the eyes of NZ immigration she has no reason to return to Thailand.
I generalized a little this would not apply to all Thais
We did arrange a letter from her employer indicating she had been given time off and was expect to return to work at the end of Dec
Also a letter from her landlord confirming there was a long term tenancy agreement in place that she was committed too.
As a sponsor I am responsible for any costs she may incur while in NZ such as medical expenses,(witch included a $9 k maternity bond), accommodation, and potential deportation costs if she overstays or breaks the conditions of a visitor visa.
The maternity bond is not paid up front but I think I`m safe on that one !!!
Have you given any thought as to how you are going to keep her occupied (other than the obvious ) during the visit?
You didn't say how long she was staying, but you can only do so much touristy stuff. Plus, if it goes well and turns out to be an indefinite stay, keeping her mind engaged and helping her adjust to New Zealand could be a real challenge.
I have a story that I might share in another thread about a Korean girl that I let shack up with me a couple of years ago, and I can tell you to expect some mood swings and frustration to enter into the equation at some point. My situation was very different than yours, but from the aspect of having a person in your life and house from another culture, there are some similarities.
In addition, her being a ladyboy might even add to feelings of isolation; even if there is a Thai community in your city, would she be able to mix with it, and have a few friends outside the home?
Sending her to school to take English lessons is an obvious thing you can do, but that probably isn't enough.
Not trying to be Mr. Negative here, but any cross-cultural relationship has challenges, and they are only exacerbated when one person is having trouble adapting to living in a new country.
If I remember correctly, you mentioned that you were considering moving to Thailand at some point, right?
That might make the prospect of living with her long-term easier in some regards, as I think that Thais don't do that well being cut off from their family and network of friends.
Then again, as I said earlier in the thread I am a cynic on relationships and romantic love. Plus, I have a tendency to over-think simplistic matters.
So filter my advice accordingly.