text not getting justified

Question

I have written the following tex code

\documentclass[12pt]{book}
\usepackage[contents={}]{background} 
\usepackage{fontspec}
\setmainfont{Constantia}

\begin{document}
\LARGE
    
\chapter{Prayer}
True Gurus are very rare in this world, and of course, neither the true disciple! Only one who is full of Viveka (discrimination) and Vairagya (dispassion) is a qualified disciple. 

\end{document}

This produces the text as shown below :

As we can see, this text is left aligned but somehow it is not getting right aligned (see the 3rd line) as well. How can i make it justified (both left & right aligned) ? Just to show the problem, i have written a small text here, but the problem is seen at many places. I see that by default the text in latex is justified, but not sure why it is not seen here. Can anyone please let me know why this issue is coming and how to resolve it. Thanks.

Answer 1

The issue will manifest itself when TeX is unable to break the line. It will emit an Ovefull hbox message and then manual intervention will be required to resolve the problem.

It can be solve by hyphenation, justified, ragged-right text, re-writing, an so on. It can happen with any font. In this example I used the default, Latin Modern Regular.

Another alternative to avoid the overfull lines is to use \emergencystretch to allow the inter word spaces to stretch.

I was introduced by Donald E. Knuth in TeX 3.0 together with a third pass for TeX’s line-breaking algorithm. (To discourage authors from using high values of the parameter \tolerance, which affects the entire document.)

The default value is 0pt, and can be augmented on a specific paragraph if the author (or editor) is unwilling or unable to change the text.

The best value to use and its aesthetic impact depends on the number of spaces between words in the column width and the number of characters to move to the next line.

From The optimal value for emergencystretch

Whatever value for the parameter \emergencystretch is used, the output should be checked to see if it does not create awful looking lines. The author of a text should think about a textual change before eliminating overfull lines with \emergencystretch.

Some experiments:

\documentclass[12pt]{article}
\usepackage{fontspec}

\begin{document}
    
    \hsize=379pt
    
    column width => \the\hsize
    
    emergencystretch default => \the\emergencystretch
    
    \LARGE
    True Gurus are very rare in this world, and of course, neither the true disciple! Only one who is full of Viveka (discrimination) and Vairagya (dispassion) is a qualified disciple. 
    
    \bigskip
    
    \normalsize \emergencystretch=7pt
    
    emergencystretch => \the\emergencystretch
    
    \LARGE
    True Gurus are very rare in this world, and of course, neither the true disciple! Only one who is full of Viveka (discrimination) and Vairagya (dispassion) is a qualified disciple. 
    
    \bigskip
    
    \normalsize \emergencystretch=0pt
    
    emergencystretch => \the\emergencystretch\, (Using hyphenation)
    
    \LARGE
    True Gurus are very rare in this world, and of course, neither the true disciple! Only one who is full of Viveka (discrimination) and Vai\-ragya (dispassion) is a qualified disciple. 
    
        \bigskip
    
    \normalsize \emergencystretch=0pt
    
    emergencystretch => \the\emergencystretch\, (re--written)
    
    \LARGE
    True Gurus are very rare in this world, and of course, neither the true disciple! Only one who is full of  Vairagya (dispassion) and Viveka (discrimination) is a qualified disciple. 
    
\end{document}

Answer 2

Add the following to your document preamble and see if it solves your issue:

\usepackage{ragged2e}
\justifying