感兴趣 (gǎn xìng qù) is a separable verb phrase meaning 'to be interested (in something)'. It is used with 对 (duì) to indicate the object of interest, and the phrase can be split, e.g., 感什么兴趣. Unlike 有意思 (yǒu yì si), which describes something as 'interesting', 感兴趣 expresses a person's feeling of being interested.