Could you say more about the question of whether she’s an introvert or an extrovert? How would a Thai man or woman tend to view this? You mention this as an important question for Thai men, I would like to understand more about this.
if you’re still in Singapore stay there until next week, then return to Thailand (make sure you have a return ticket). You will get a 30 day visa exempt entry, which you can extend inside Thailand for an additional 30 days. This will get you to the last week of February.
If you have a specific date you need to be in Thailand until then time your entry so that date is 60 days away, remembering that the date you arrive is counted as day 1.
I wonder if your dental treatments might qualify you for a 1 year medical visa? In that case, Thai immigration would understand why you’re coming so often.