Never scale tables. It make inconsistent font size used in table.
Since you not provide any information about your document layout, we can only guess about it. So, the MWE (Minimal Working Example) below can gives only an idea, how you can solve your problem:
- in table use smaller font size
- reduce separation between columns
- wrote column headers in two lines
In MWE are used tblr environment of tabularray package with S columns of siunitx. Using them the table code is shorter and simpler, and numbers are nicer alignet:
\documentclass{article}
\usepackage[margin=25mm]{geometry}
%---------------- show page layout. don't use in a real document!
\usepackage{showframe}
\renewcommand\ShowFrameLinethickness{0.15pt}
\renewcommand*\ShowFrameColor{\color{red}}
%---------------------------------------------------------------%
\usepackage{tabularray}
\UseTblrLibrary{booktabs, siunitx}
\begin{document}
\begin{table}[ht]
\small
\begin{tblr}{colsep=3pt,
colspec = {@{} l *{10}{X[c,m, si={table-format=2.0}]} @{}},
row{1,2} = {guard}
}
\toprule
\SetCell[r=2]{m} Condition
& \SetCell[c=4]{c} EMO RE
& & & & \SetCell[c=6]{c} Pairwise Comparisons
& & & & & \
\cmidrule[r]{2-5}
\cmidrule[r]{6-11}
& Angry
& Fearful
& Happy
& Neutral
& Angry-Fearful
& Angry-Happy
& Angry-Neutral
& Fearful-Happy
& Fearful-Neutral
& Happy-Neutral \
\midrule
Congruent
& 5 & 8 & 12& 2 & 5 & 8 & 12& 2 & 8 & 12 \
Incongruent-Body Focus
& 6 & 9 & 2 & 6 & 5 & 8 & 12& 8 & 12 & 2 \
Incongruent Voice Focus
& 7 & 9 & 5 & 8 & 5 & 8 & 12& 2 & 8 & 12 \
\bottomrule
\end{tblr}
\end{table}
\end{document}

Red lines show pages' text block borders.
Addendum:
Reproduction table style in @Mico answer (+1) with rblr tableČ
\documentclass{article}
\usepackage{geometry}
\usepackage{tabularray}
\UseTblrLibrary{booktabs, siunitx}
\usepackage{caption}
\newlength\mylen % for second example
\begin{document}
\begin{table}[htb]
\settowidth\mylen{Incongruent-}
\begin{tblr}{colsep=2pt,
colspec = {@{} Q[l, m, wd=\mylen, cmd={\hangafter=1\hangindent=1ex}]
*{10}{X[c, m, si={table-format=2.0}]}
@{}},
row{1,2} = {guard}
}
\toprule
Condition
& \SetCell[c=4]{c} EMO RE
& & & & \SetCell[c=6]{c} Pairwise Comparisons
& & & & & \
\cmidrule[r]{2-5}
\cmidrule[r]{6-11}
& Angry
& Fearful
& Happy
& Neutral
& Angry-Fearful
& Angry-Happy
& Angry-Neutral
& Fearful-Happy
& Fearful-Neutral
& Happy-Neutral \
\midrule
Congruent
& 5 & 8 & 12& 2 & 5 & 8 & 12& 2 & 8 & 12 \
Incongruent-Body Focus
& 6 & 9 & 2 & 6 & 5 & 8 & 12& 8 & 12 & 2 \
Incongruent Voice Focus
& 7 & 9 & 5 & 8 & 5 & 8 & 12& 2 & 8 & 12 \
\bottomrule
\end{tblr}
\end{table}
\end{document}
