Where did you find the quote? did he make it originally in Japanese because if you find the original Japanese even if it is Kanji paste it and we can more easily turn it into the Japanese he meant.
The quote translated online from English then back into Japanese will surely lose some nuance.
Anyway I am
not fluent in Japanese in any way so this will not be fluent and maybe not accurate but should get the point across in a simple way.I am also interested to see how far off I am
大人皆さんの胸は子供の心と思います。それから, 私たちに大人の行動を段々教える。
おとな みんなさん の むね は こども の ここ ろ と おもいます。
Adult Everyone's chest is child's heart I think.
それから、 わたしたち に おとな の こうどう を だんだん おしえる。
therefore, us to adults behavior gradually teach