I came to Thailand with a booked return flight 88 days later. Arrived at Suvarnbhumi international, 60 days visa exempt no problem.
To do the right thing by Thai authorities I went to my local immigration office (regional, I won't say which) to extend my stay by 30 days and pay my 1900 bhat. The immigration officers were very helpful, I had all the correct paperwork and a Thai friend to help with language, if required. It was.
Surprisingly, it appeared they wondered why I didn't just do a border run to get a further 60 days visa exempt. I got the impression they felt that was the easiest way and not to have to bother with all the paperwork.
I assume you mean the TDAC. The Thailand Digital Arrival Card. I did that within the 3 days prior to my arrival. Iy is easy to do. That is not related to a visa or visa exemption. Yes I agree it is a bit confusing with all the different visas. But once you find the visa that suits your circumstances, it should be easier. My point was it was clear to immigration that I intended to stay 90 days, which was greater than my 60 day visa exemption stamp, but I was not questioned about my intentions regarding extension of this period up to 90 days.
I arrived from Australia in mid May with a return flight booked in 90 days from entry. My intention is to extend my 60 day visa exemption by a further 30 days.
I was not asked anything at BKK airport immigration and had my passport stamped with 60 day visa exemption.
Rule No 1: Don't buy or spend on anything in Thailand that you are not prepared to lose or walk away from. This is regardless of the sincerity of your lady. Follow the rule and you cannot be disappointed.