the children's growing fascination with his strange behavior [=their increasing strong interest in his behavior]孩子们对他的古怪行为产生的越来越浓厚的兴趣

I've studied her paintings with fascination. [=a strong desire to look at and think about them]我非常投入地研究了她的画作。

Her paintings have/hold a real fascination for me. [=they interest me deeply]她的画作令我十分着迷。