If you are a great believer in something, you think that it is good, right, or useful.
例句
Mum was a great believer in herbal medicines.媽媽特別相信草藥。
N-COUNT
（宗教）信徒，信仰者
A believer is someone who is sure that God exists or that their religion is true.
例句
I made no secret of the fact that I was not a believer.我毫不掩飾我不信教。
英漢詞典釋義
n.
信仰者,信徒
My mother was a great believer in horoscopes all her life.我母親一輩子對占星術篤信不移。Teddy is a great believer in finding happy medium.特迪是個十足的中庸之道的信仰者。
相信(尤指某物效能)的人
The boss was a firm believer in developing strong teamwork.老板對培育堅強團隊精神的重要性深信不疑。I’m a firm believer in the benefits of exercise.我對運動的好處堅信不疑。I’m a firm believer in always telling the truth.我堅信應該說真話。