Jealousy is a multifaceted emotional phenomenon that cannot be explained solely by a lack of self-confidence.

The Complex Roots of Jealousy

Jealousy is a multifaceted emotional phenomenon that cannot be explained solely by a lack of self-confidence. Of course, low self-esteem and insecurity, as noted in one source, can exacerbate this emotion. For example, it is stated:
"If a person does not believe in themselves, their relationships with others will not be solid. Jealousy is often a consequence of low self-esteem and insecurity." (source: link txt)

However, beyond personal insecurity, there are other causes for the emergence of jealousy. Jealousy can also arise as a reaction to inner fears, as indicated by another quote:
"The matter is clear: you don't love him, you hurt him, you didn't understand him. Jealousy is caused by fear." (source: link txt)

Another important aspect is interpersonal relationships, where competition and comparison with others play a significant role. For example, it is mentioned that:
"Rivalry brings difficulties to everyone, but it shows its sharpness in situations where human relationships are dominated by selfishness. In a state of rivalry, there is a constant comparison of oneself with others." (source: link txt)

Thus, although a lack of self-confidence is a significant factor, jealousy extends far beyond it and encompasses a range of other causes—from fear and emotional pain to competition and egocentrism. This makes jealousy a complex phenomenon that requires consideration of many internal and external factors to fully understand its origins.

Supporting citation(s):
"If a person does not believe in themselves, their relationships with others will not be solid. Jealousy is often a consequence of low self-esteem and insecurity." (source: link txt)
"The matter is clear: you don't love him, you hurt him, you didn't understand him. Jealousy is caused by fear." (source: link txt)
"Rivalry brings difficulties to everyone, but it shows its sharpness in situations where human relationships are dominated by selfishness. In a state of rivalry, there is a constant comparison of oneself with others." (source: link txt)