After Jeanne Alter forcefully performed some Mana Transfer with Gudao, Gudao said she shouldn't do such stuff so recklessly with anyone, but with someone she loves.
Jalter then "reminisces" about her "past", where she didn't really had a chance to, as she was raped and humiliated prior to her execution.
Of course, all these flashback isn't actually real, as Jalter is just a manifestation of Caster Gilles de Reis' despair, which (according to doujin artists) includes the despair of Jeanne possibly being raped during her captivity. The real Jeanne d'Arc (at least in the Nasuverse) died a virgin.
The real Jeanne d'Arc died a virgin though. The anglos did the impossible to find any fault on her and the best they could find was a crime of crossdressing, despite being them who gave her male clothes while captive. Some dude tried indeed to rape her and he only got his testicles crushed for the troubles.
The real Jeanne d'Arc ironically had some of Jalter's traits.