All 5 Uses

positive
in
Harry Potter (#3) and the Prisoner of Azkaban
(Edited)

In fact, by Hagrid's usual standards, he was positively cute.
Chpt 11

positively = absolutely (used for emphasis)
He positively fled when I offered to crystal gaze for him —
Chpt 11
He was positive that there was nothing wrong with the Firebolt now, but what sort of state would it be in once it had been subjected to all sorts of anti-jinx tests?
Chpt 12 *

positive = certain
Professor Lupin continued, "The Patronus is a kind of positive force, a projection of the very things that the dementor feeds upon — hope, happiness, the desire to survive — but it cannot feel despair, as real humans can, so the dementors can't hurt it."
Chpt 12 *

positive = good or beneficial
"You're going to be fine," Hermione told him, though she looked positively terrified.
Chpt 15

positively = absolutely (used for emphasis)

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.