Meaning of the word "only the wearer knows where the shoe pinches" in English

What does "only the wearer knows where the shoe pinches" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

only the wearer knows where the shoe pinches

US /ˈoʊnli ðə ˈwerər noʊz wer ðə ʃuː ˈpɪntʃɪz/
UK /ˈəʊnli ðə ˈweərər nəʊz weə ðə ʃuː ˈpɪntʃɪz/
"only the wearer knows where the shoe pinches" picture

Idiom

only the person experiencing a problem or situation truly understands its difficulty or pain

Example:
She looks happy, but only the wearer knows where the shoe pinches regarding her family struggles.
I can't judge his stress; only the wearer knows where the shoe pinches.