@Ghajik Okay, thanks, but I still think it's a hell of an archaic word. See the OED:
saintess
(ˈseɪntɪs)
[f. saint n. + -ess.]
A female saint.
1449 in Nichols Illustr. Manners Ant. Times 132, Y beseche al the glorious seyntes and seyntesses in heaven [etc.].
1509 Fisher Funeral Serm. C'tess Richm. Wks. (1876) 306 The moost blessyd company of sayntes and sayntesses.
1625 Jackson Creed v. xxviii. §1 Saints are not our immediate intercessors, but some Saintesse may make immediate intercession.
1737 Gentl. Mag. VII. 287/2 This Maid of Orleans, whom divers French Historians picture out as a Saintess.
1865 Freeman in W. R. W. Stephens Life & Lett. (1895) I. 334, I made a speech likening her to all the crowned saintesses in ecclesiastical history.
I knew the word in French, but I'd never seen it before in English. It's okay if your translator wants to give the translation a historical flavour. I'd personally use simply "saint".
Keep up the good work!