What alternatives exist for proving an income of 40,000 baht per month for a Non-O marriage visa in Thailand instead of depositing 400,000 baht in a bank?

To prove a monthly income of 40,000 baht for a Non-O marriage visa instead of maintaining a 400,000 baht deposit, you typically need to show income from a work permit in Thailand. Some immigration offices may accept other proofs such as an affidavit from your embassy, although many embassies do not provide this service. If an affidavit isn't an option, the common workaround is to initially deposit the 400,000 baht in a Thai bank and then demonstrate the monthly income for any future extensions.