The rules from SVB are quite complicated. Personally I would not ask information on a public form.
Visit the website from the SVB in NL, there you find all information you want to know. Start with the information "AOW en gezamenlijke huishouding", this brochure you can download in PDF format. There are much more brochures that are useful to download and read.
You receive the "married pension" not only when you are married, also when your child reach a certain age, have a live-in housekeeper, and much more.
As Groenen said you have to fill every year a Life Certificate which must be approved by the SSO (Social Security Office). The SSO makes a copy from the certificate and your passport and keep this in your personal file they have about you.
SVB NL works together with the SSO in Thailand. The way they check if the information on the Life Certificate is true can be done in many ways.
1. SVB send an officer to Thailand and check people together with officers form the SSO and the police in a house visit.
2. The SVB give a list to the SSO with details of people they want to be checked. In that case the SSO checks if your address is correct with immigration and the local amphur. furthermore when they have doubts about anything they will visit neighbors and interrogate them about you and if you really live alone, are not married, etc.
3. The SVB has much more ways to check you, by Dutch law they are allowed your social media accounts, bank accounts (to see if you support another person or make regular payments to a person), and ask the Ministry of Finance for details about you.
If appears you have lied about your personal situation you are in deep trouble.
Aside from paying back the difference between the single and the married pension you will get a fee of 150% and SVB will file a complain about fraud with the Ministry of Justice, which will give you a criminal record for the rest of your life.
Aside of the AOW, apply for a DigiD before you receive your pension.
A DigiD save you a lot of hassle in communication with the SVB. sending your Life Certificate back after approval, apply for your AOW, and more.
Don't try to fool the SVB, you will lose for sure. It is impossible to hide your Thai wife or girlfriend forever. The SVB has many ways to check you.
Sorry for my bad English, I am Dutch and not English.
I have had my problems with the SVB too but was able to solve them. Same like the Ministry of Finance they are not easy to communicate with and you must be able to prove everything.
In case you want to know more you can PM me, then I can write in Dutch which is easier. about this subject.
Good luck with getting the AOW you are looking for. Henri.