Final answer:
Benvolio may not tell the whole truth to prevent harm, protect others, or avoid negative outcomes from honesty. This behavior is common in literature, where characters balance honesty with the potential impacts of their disclosures.
Step-by-step explanation:
The most likely reason that Benvolio doesn't tell the whole truth is tied to concerns for safety, protection of others' feelings, or a fear of the consequences that honesty might bring. In various literary contexts, characters may withhold the truth to avoid potential danger, protect someone they care about, or control the situation. For example, characters may hesitate due to the hazard their truth could pose to others' well-being and happiness. This avoidance can stem from a place of love, self-preservation, or complex emotions that lead characters to struggle with their conscience about when and how to reveal critical truths.