, my girlfriend (wife now) was denied a visa on her first application, and I was an embassy badge holder at the time (1996 or 1997). The next application, I brought supporting documents, signed statements, and a wedding invitation with her name on it for my sisters wedding. We were also travelling to the States for 2 weeks. The embassy gave her a 2 week visa, with my name stamped on it as accompanying her. If she gets a visa and returns to Thailand, subsequent visa will be incredibly easy.
, bring everything you can. You might even write a statement explaining that you will accompany her to the United States, provide financial support while there, and ensure her return to Thailand.
Visas for Thais to visit the states are difficult to get. It's on her to prove she's not going immigrate to the US.
This is kind of true, in the old days if you were called to the dreaded "Window 11" with the Thai dragonlady your application was rejected and come get your passport back.
The interviewer will speak Thai. Your girlfriend needs to show a compelling reason for her return to Thailand. Does she own land? Have employment that she needs to return to? Have something that will show the interviewer she has a reason to exit the United States. Bring whatever supporting documents that she might have.
You can extend it any time before your 60 day stamp expires. I extended mine today for 30 days and I have 6 days left on my old stamp. It gets extended from the stamp end date, regardless of when you do it.