It's often used to describe the pleasant scent of things like:
* Flowers: "Sakura ga kaatte imasu" (桜が香っています) - "The cherry blossoms are fragrant."
* Food: "Kono pan wa kaaru" (このパンは香る) - "This bread is fragrant."
* Perfume: "Kono kōsui wa kaaru" (この香水は香る) - "This perfume is fragrant."
It can also be used more generally to describe the act of smelling something.
Examples:
* "Kaoru mono ga suru" (香るものをする) - "Something smells."
* "Nani ka kaatte imasu ka?" (何か香っていますか？) - "Do you smell something?"
It's important to note that "kaaru" is usually used for pleasant scents. If you want to express an unpleasant smell, you would use a different word like "kusai" (臭い).