Its all about the invitation letter. Be honest. Dont follow a formatted letter. Obviously pass the criterea, you need money enough to take care of her, 6 months bank statements, 6 month wage slips. She needs biometrics and 'reason to return" doesnt have to be a job, can be family, children property etc. You then need to prove where she will be staying, mortgage, deeds etc. Also 2 x utility bills. Oh and if youve met her less than 2 years, no chance. If youve met her in person and have photos good to go. Then finally photocopies of all your stamped passport pages and first page from both. Be careful that the stamps match when you say you visited her in Thailand if they dont, its a reject.