firm and dependable
staunch - firm
The word ‘staunch’ is used to express loyalty and steadfastness with an emphasis on fortitude and resolution against things that would threaten what you are faithful to. Such support is unwavering and usually without conditions. It is not necessarily always a person, country, or organization that this is used in reference to, often it can be a set of ideas or principles.
I’ve always been a staunch supporter of Alice, so I don’t know why she’s accusing me of betraying her.
That country is our staunchest ally. We must protect them at all costs.
The lawyer was a staunch defender of human rights, and a champion of democratic values.