他是一位虔诚的佛教信徒。

He is a devoted ___believer in Buddhism.

她是个坚信冥想能带来平静的人。

She's a firm ___believer in the calming power of meditation.

作为一名环保理念的坚定支持者，他坚持骑自行车出行。

As a strong ___believer in environmental protection, he insists on cycling to work.