\documentclass{book}

\usepackage{amsthm}

\usepackage{xepersian}

\makeatletter
\bidi@patchcmd{\@makechapterhead}{\thechapter}{\tartibi{chapter}}{}{}
\bidi@patchcmd{\chaptermark}{\thechapter}{\tartibi{chapter}}{}{}
\makeatother

\settextfont[Scale=1]{XB Zar}
\setdigitfont{PGaramond}
\setlatintextfont{Times New Roman}

\theoremstyle{thorem}
\newtheorem{theorem}{قضیه}[section]

\SepMark{-}

\begin{document}
\tableofcontents

\chapter{فصل اینجا}
\section{بخش اینجا}
\subsection{زیر بخش اینجا}

\begin{theorem}
شرح قضیه
\end{theorem}

\end{document}