Be a great believer in (something) phrase
The word "great" can be replaced by "firm".
To have a strong belief that something is good, right or important
So as not to be exhausted during this stressful period, I'm a great believer in unwinding on the weekends.
I’m a great believer in working out so that I live healthily.
My auntie is a great believer in the zodiac sign as she thinks it would give her wealth and happiness.
To decide to believe someone‘s saying although they may not tell the truth
1. If you hang your hat on something, you depend or reply on it.
2. If you hang your hat on something, you believe or trust it.
If you take something as gospel, you definitely believe it without without any hesitation.
If you take someone’s word, that means you trust what they are saying.
The phrase "be a great believer in (something)" is followed by a noun, noun phrase or gerund.