Sentence:  Oh love! how perfect is thy mystic art, / Strengthening the weak, and trampling on the strong, / How self-deceitful is the sagest part / Of mortals whom thy lure hath led along— / The precipice she stood on was immense, / So was her <WSD>creed</WSD> in her own innocence. 
Meaning of the word marked with <WSD> tags:  The fact of believing; belief, faith.