All 3 Uses

positive
in
Monster, by Walter Dean Myers
(Edited)

She doesn't sound that positive.
p. 110.7

positive = certain
He's very much involved with depicting his neighborhood and environment in a positive manner.
p. 235.5 *

positive = good or beneficial
Here is a Black woman, uneasy about her role in identifying a young Black man, who still had the courage to testify before you and to positively identify Mr. King.
p. 258.9 *

positively = with certainty

Definitions:

(1) (positive as in: I'm absolutely positive!)
certain (having no doubt; or used for emphasis)
(2) (positive as in: had a positive effect)
good or beneficial
(3) (positive as in: positive feedback from my boss)
approval or agreement
(4) (positive as in: a positive attitude)
optimistic (expecting or focusing on good things); or agreeable
(5) (positive as in: The test came back positive.)
found a condition or substance to be present
indicating the presence of something being tested for -- especially a disease, condition, or substance
(6) (positive as in: a positive number)
greater than zero (of a number)
(7) (meaning too rare to warrant focus)
See a comprehensive dictionary for less common meanings of positive including some in the fields of electricity, physics, chemistry, medicine, philosophy, and grammar. Note that most all senses of positive indicate that something is good or present.