expression
love someone so much you're blind to their faults; apple of one's eye
Idiomatic expression describing doting affection, often for a child or grandchild, where the person can do no wrong in one's eyes. Literally 'it wouldn't hurt even if you put them in your eye'.
孫は目に入れても痛くないほど可愛い。
My grandchild is so adorable I could just eat them up.
彼女は一人娘を目に入れても痛くないように育てた。
She raised her only daughter as the apple of her eye.
A Japanese idiom literally meaning 'it wouldn't hurt even if you put them in your eye', expressing the idea that someone is so precious that even something normally painful would be bearable. The exact origin is uncertain, but it is a traditional expression of extreme parental or grandparental affection.