Sorry, so as not to raise false hopes--it takes a lot more than that--there are a number of categories that are looked at in qualifying for a US visa---money in the bank is one--but it must show a lengthy record of deposits and savings from a well-paying job, that she has held for some time and will be allowed to return to,
Other categories include, previous travel outside of Thailand and evidence of her return per those travels, does she own property, her education, her family ties (does she have children, elderly parents, etc) all things that would compel her to return to Thailand.
And, often, from reports of friends, even with satisfying many of these categories, the visa is still denied--as it is at the discretion of the visa officer
--have read that even those applying for a fiance visa find that the process and evidence needed can take 6 to 9 months, or sometimes longer.
not an easy or pleasant process at all--but, nothing ventured, nothing gained---but, one last mention--if you can realistically look at the above and
understand that she cannot present evidence of those things, please know that each application used to require a non-refundable fee of
$100--it may be even more now and many hours of waiting to even submit an application, then they give you a date, often weeks or more into the future to return for an interview or decision.