Learner's definition of FASCINATE
to cause (someone) to be very interested in something or someone
His strange behavior fascinated the children. = He fascinated the children with his strange behavior.
Her paintings fascinate me. = I'm fascinated by/with her paintings.
a question that fascinates both biologists and anthropologists
the children's growing fascination with his strange behavior [=their increasing strong interest in his behavior]
I've studied her paintings with fascination. [=a strong desire to look at and think about them]