My Thai ex-GF was given a 10 year, multi-entry 1st time. However...
We were able to show a long-term relationship, both through social media posts and mail that came to the same address in each of our names. In addition, we had extensive travel around SE Asia and also a month in Australia. She was a student, no home ownership, no income, only support from me. We made photocopies of our entry/exit stamps from both of our passports showing we traveled together many times (>12??). Establishing that we had a relationship and that she depended on me was key. I showed my work permits and contracts over many years of stay in Thailand. Even though I am US citizen, I was able to establish that I was returning to Thailand. Probably 80 or so pages of documentation. Also, this was about 10-11 years ago.
She was working in a bar in PTY when I met her, but that never came up in any context.