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unaffected and sincere, with fortitude and vigor (vigour)
質実剛健な校風が伝統として受け継がれた。
The school's culture of sincerity and fortitude was passed down as tradition.
質実剛健を旨とする教育方針を掲げた。
They adopted an educational policy centered on sincerity and vigor.
質実剛健な人柄が周囲の信頼を集めた。
His sincere and robust character earned the trust of those around him.