Underwear will not affect fortune. Fortune is a subjective concept, which is influenced by many factors, including personal behavior, mentality and surrounding environment. Underwear is close-fitting clothing. Its comfort, quality, style and color may affect people's mood and health, but it will not directly affect people's fortune.
So wearing underwear will not affect your fortune, but if you think it may affect your mood or health, then you can choose to discard it.