Compatibility summary
You will need a travel adapter in Brunei; plug types used there differ from Brazil. Voltage differs by more than 20% — a voltage converter may be needed for some appliances.
Plug comparison
Brazil plug types: C N
Brunei plug types: G
There is no common plug type between Brazil (C N) and Brunei (G). You need a travel adapter.
Voltage comparison
Brazil: 127V, 60Hz
Brunei: 240V, 50Hz
Voltage converter recommended (Brazil 127V vs Brunei 240V).