Final answer:
Anis best illustrates the use of a defense mechanism known as reaction formation, where a person acts opposite to their true inclinations to disguise their true feelings or thoughts.
Step-by-step explanation:
The defense mechanism being illustrated in the given scenario is reaction formation. Anis acts confident and sure of himself, which is opposite to how he may truly feel (unconscious insecurity and self-doubt). Reaction formation is a defense mechanism where a person expresses feelings, thoughts, and behaviors that are opposite to their true inclinations.
For example, Joe, who deep down feels sexually attracted to males but consciously believes being gay is wrong, may make fun of a gay peer to mask his own feelings. In a similar way, Anis may act confident and sure of himself to protect himself from experiencing insecurity and self-doubt.