Look at the poor thing! So much heavy metal! Is this any way to treat such a noble and brave warrior of the faith? Though she is obviously distressed by the extent of her restraint, I think the real, powerful regret we see in her eyes comes from something more. She believes, in her heart of hearts, that she fully deserves what she is and will experience. To most people, the “crime” which placed her here would probably seem harmless. But she is not most people. She holds herself to a higher standard. She is a true believer. Another might rail against the way they roughly stripped her of her possessions and locked her slender form in heavy shackles. Less noble folk might have claimed that her jailers were abusing their authority to visit such harsh treatment upon her for so minor a transgression. But not her. She accepts their judgment because, in truth, she judges herself even more harshly than they do.
She’s not the first paladin to fail to uphold their vow of chastity. If she’s lucky the head of her order will allow her to return to her duties with time served and a permanently locked chastity belt. More likely though she’s serve a decade or two and then be packed off to a nunnery all while still being permanently locked in that belt.