\documentclass[11pt,a4paper]{book} 
\usepackage{tikz}
\usetikzlibrary{positioning}
\usepackage{pgf}
\usepackage{verbatim}
\usetikzlibrary{decorations.pathmorphing}
\usetikzlibrary{decorations.text}
\usepackage{xepersian}
\settextfont[Scale=1]{XB Zar}
\setlatintextfont[Scale=1]{Linux Libertine}
\setdigitfont[Scale=1]{XB Zar}
\begin{document}
\begin{tikzpicture} 
       \path [decorate,decoration={text along path,
        text={من همیشه مزاحم اوقات دوستان می شوم. }}]
        (0,0) sin (-1,1) cos (-2,0) sin (-3,-1) cos (-4,0) sin (-7,-1);
\end{tikzpicture}
\begin{tikzpicture}
\draw [help lines] grid (3,2);
\path [decorate,decoration={text along path,
text={a big |\color{green}|green|| juicy apple.}}]
(0,0) .. controls (0,2) and (3,0) .. (3,2);
\end{tikzpicture}
\end{document}