velvet glove

A gentle, sweet, or unassuming appearance or disposition, often that which conceals a severe, forceful, and uncompromising nature. The principal has been ruling the school with a velvet glove, trusting students to behave and follow the rules of their own accord. Not surprisingly, the place is in near-constant chaos. The new leader of the country rose to power with promises of democracy and equality, but as his despotic intentions came to light, he soon proved to be an iron fist in a velvet glove.