“不倦的”用英语怎么说？

他们艰苦的工作和不倦的勇气拯救了我们.Their toils and tireless courage were our salvation.从那时候起他变做世上最自谦, 最有礼貌, 最屡求不倦的求婚人了.From that time he was the most humble, modest, and importunate man alive in his courtship....