Final answer:
A personality researcher would say Belinda, known for kindness and generosity, scores high on the trait of agreeableness, part of the Big Five personality traits.
Step-by-step explanation:
A personality researcher studying traits would likely say that Belinda, being considered the kindest and most generous among her friends, is very high on the trait of agreeableness. This is one of the five major dimensions of personality according to the Big Five personality traits theory, which also includes openness, conscientiousness, extraversion, and neuroticism. High agreeableness is characterized by attributes such as trust, altruism, kindness, affection, and other prosocial behaviors.