Relations between men and women
In Brunei's culture, it’s not allowed for men and women who aren’t blooded relatives or married, to be alone together. This is the same in some countries in the Middle East, including Saudi Arabia. This only applies to Bruneian Muslims, but punishments can sometimes be harsh especially when authorities suspect adultery. And committing adultery is a big no-no. It is considered illegal in Brunei and can carry an archaic punishment such as stoning to death. This is unlikely to affect tourists unless it involves a Bruneian or a Muslim.
Moreover, in Brunei, unmarried couples are not allowed in a hotel room due to adultery laws. If you’re not married, you need to get separate rooms. This still applies if you’re in a long-term relationship and haven’t tied the knot. The law can be murky and exceptions are sometimes made for foreign tourists. Call the hotel and double-check before booking a room if you’re in this situation.