分析下句子：Belief is a feeling of certainty that something exists

分析下句子：Belief is a feeling of certainty that something exists, is true, or is good.
Belief is a feeling of certainty that something exists, is true, or is good. 这句中that 后面是不是定语从句,that修饰certainly?我一开始会觉得,that...修饰feeling of certainly,谁帮解释下,然后翻译下,不胜感谢.