Imagine someone walks into your room. If that person is wearing really nice perfume, after they leave, the nice smell stays behind, right? You remember them and smile. But if someone leaves an old banana peel under the bed, it's going to rot and leave a horrible smell. Everyone will want to stay away.
The Bible says our name is just like that. Whoever is kind, a good friend, and fair leaves a "perfume" in people's memory (everyone remembers them fondly). Whoever is mean and selfish leaves a name that "rots" (nobody wants to remember).