藏着一个让人心碎的秘密
[zàng zhe yī gè ràng rén xīn suì de mì mì]
This implies a person who harbors an intensely sad secret within them which has the capacity to affect those around them once it’s uncovered. Someone might pick this kind of username due to their belief in keeping some matters undisclosed and to maintain emotional distance from others, while simultaneously expressing pain they've suffered silently