He is the more diligent of the two.
Your sister is the most diligent of all my friends.
The students are for the most part diligent.
The students are for the most part diligent.
This is so enduring as to make even the most diligent worker give up.
George is the most diligent boy in our class.
Tom works more diligently now.
Tom is the most diligent student in his class.
Tom is the most diligent student in class.
You cannot be too diligent.