The father taught his son that facing difficulties with courage is true manhood.

manhood 是由名词 man（男人）加上后缀 -hood 构成的名词。-hood 表示"状态、性质、身份"，所以 manhood 的字面意思是"作为男人的状态或品质"，引申为"男子气概、成年男子身份"。