Faith is a noun.
faith noun
1. Absolute certainty in the trustworthiness of another:
belief, confidence, dependence, reliance, trust.
2. Mental acceptance of the truth or actuality of something:
belief, credence, credit.
3. A system of religious belief:
confession, creed, denomination, persuasion, religion, sect.
4. Those who accept and practice a particular religious belief:
church, communion, denomination, persuasion, sect.
https://www.thefreedictionary.com/truth