Compatibility summary
Your South Korea plug may fit in Denmark outlets, as both use at least one common plug type.
Plug comparison
South Korea plug types: C F
Denmark plug types: C K
Both countries share at least one plug type (C F and C K), so some plugs may work without an adapter. Check your appliance.
Voltage comparison
South Korea: 220V, 60Hz
Denmark: 230V, 50Hz
Voltage difference is within a range many devices tolerate; check your appliance label.