How to remove blank page when using newpage

By the way, after creating cover on bookclass, I tried to use newpage. When I was trying to type random sentence, it works fine.

But, when I added this earlier:

begin{center}
       chapter*{textbf{TITLE}}
end{center}

It created a blank page between the cover and the chapter I’m working on.

How to fix this?

My code is:

newpage
begin{center}
       chapter*{textbf{TITLE}}
end{center}
 %text here

---

EDIT

I’ll show my full codes. I’m splitting my TeX files into 3 part and using include{...}

documentclass[a4paper,12pt,oneside,openany]{book}
usepackage{pgf, tikz}
usepackage[a4paper, inner=4cm, outer=3cm, top=4cm, bottom=3cm]{geometry}
usepackage[onehalfspacing]{setspace}
usepackage{fancyhdr}
usepackage{titlesec}
usepackage{setspace}
fancyhf{}
cfoot{thepage}
linespread{1.5}
pagestyle{plain}

renewcommand{contentsname}{DAFTAR ISI}
renewcommand{listtablename}{DAFTAR TABEL}
renewcommand{listfigurename}{DAFTAR GAMBAR}
begin{document}
clearpage
thispagestyle{empty}

frontmatter %

pagestyle{fancy}   
renewcommand{headrulewidth}{0pt}
include{cover1}
include{cover2}

mainmatter %

end{document}

My codes for cover2.tex

newpage
begin{center}
chapter*{textbf{RINGKASAN}}
end{center}
addcontentsline{toc}{chapter}{textbf{RINGKASAN}}
%TEXT HERE