But a couple of tips , always give them more than they ask for , what they want to know ..
1. The relationship is real ( if you are needed as a sponsor , which is the common situation )
2 ..That she has sound reason to return
So for example over 20 years , I've had 5 seperate applications ( multiple) approved , once the first one is granted you have history it's easy , so long as it's the same applicant .
So , you financial capacity to support ( assuming required ) or your gfs wealth , proof of relationship , where is she going to be staying ?
Why is she 100 % returning to Thailand ? ( Job , assets , family etc )
Put you file together , lodge same , go for pictures , and wait ..Now if you are declined on first application , immediately reapply , with a little more , make sure all your documents are certified , translated ..and away you go .
Remember first new applicant is toughest request so please don't get disheartening feelings , you will get it though , they want to see commitment .