Repulsion is the surest test for magnetism.
The given statement is correct.
Attraction and repulsion are the properties of a magnet.
The attraction takes place when we bring a magnetic material near a magnet or when two opposite poles of a magnet are near each other. But repulsion takes place only when the like poles of the magnets are near each other. Thus, repulsion is a sure test of magnetism.
Also, a magnetic material may attract a magnet.
Hence the repulsion is the surest test of magnetism.