noun which may take the genitive case particle 'no', noun
Describes something that is truly as it should be, without falsehood or pretense. Often used in formal or literary contexts to emphasize authenticity or sincerity.
彼の真成な気持ちが伝わってきた。
His sincere feelings came through.
真成の友情は何よりも大切だ。
True friendship is more important than anything.
The exact derivation is uncertain; the kanji 真 (true) and 成 (become) or 誠 (sincerity) suggest a meaning of 'true becoming' or 'true sincerity'.