菇凉无心百毒不侵
[gū liáng wú xīn băi dú bù qīn]
The phrase 'Heartless Girl Immune to all Poisons'. It suggests that the girl has experienced many negative things, and become hardened inside - nothing could bother her anymore because of her lack of emotion due to protection built up over time. Here the character 'girl (菇凉)' also can sound like 'girl without emotions (姑娘) '.