Compatibility summary
Your Sweden plug may fit in Belgium outlets, as both use at least one common plug type.
Plug comparison
Sweden plug types: C F
Belgium plug types: C E
Both countries share at least one plug type (C F and C E), so some plugs may work without an adapter. Check your appliance.
Voltage comparison
Sweden: 230V, 50Hz
Belgium: 230V, 50Hz
Voltage difference is within a range many devices tolerate; check your appliance label.