Her interestedness in the topic was evident from her enthusiastic participation in the discussion.

She interesteth me with her stories.

I am interested in learning new languages.

I find it interestin'.

The research team discovered a unique ecosystem in the interestuarine region.

She felt a deep interestlessness in her life.

She is in her interestrus phase.

She walked interestlessly through the museum, not stopping to admire any of the artwork.

Her self-interestedness was evident in her actions.