Hontoni shizukana means something like "A truly quiet..." with the final noun, the thing that is quiet, being cut off.
So in addition to it being the opposite of what you are aiming for, it is an incomplete thought, a sentence fragment.
There are many Japanese brands that use fragmented English catch phrases or brand names. So if you don't mind having a nonsensical Japanese brand name, then Hontoni Shizukana might work for you. If the meaning is important, you'll need to compromise either meaning or length.
真の沈黙にならず Mano chinmoku ni narazu
真の静けさにならず Ma no shizukesa ni narazu
無音にならず Muon ni narazu
might work...but, clothes and silence/quietness don't really work as a pairing, so I'm not sure that the phrase is scrutable in either English or in Japanese. Is it supposed to be some kind of brand statement (expressing a value that the consumer my identify with)?