documentclass{article}

usepackage{booktabs}
usepackage{multirow}
usepackage{makecell}

newcommand{blank}{--}

begin{document}


begin{table}[h]
renewcommand{arraystretch}{1.2}
footnotesizesetlength{tabcolsep}{1pt}
begin{tabular}{llcccccc}
& & thead{bfseries Sessualità} & thead{bfseries Temperamento} & thead{bfseries Valori} & thead{bfseries Comportamento} & thead{bfseries Comunicazione \bfseries prosociale} & thead{bfseries Comunicazione\ bfseries non verbale} \
midrule

% ROW 1%
multirow{2}*{bfseries Sessualità} & Pearson's  $r$ & blank  & $textbf{-0.329$^{***}$}$ & $0.131$ & $textbf{-0.145$^*$}$ & $0.055$ & $-0.064$\
& $p$-value & blank  & $<.001$ & $0.070$ & $0.044$ & $0.449$ & $0.378$ \

% ROW 2%
multirow{2}*{bfseries Temperamento} & Pearson's $r$ &  & blank & $-0.094$ & $0.012$ & $-0.063$ & $0.125$\
& $p$-value & & blank  & $0.189$ & $0.870$ & $0.377$ & $0.082$\

% ROW 3%
multirow{2}*{bfseries Valori} & Pearson's $r$ & & & blank & $0.035$ & $0.048$ & $0.090$ \
& $p$-value & & & blank & $0.624$ & $0.504$ & $0.208$ \

% ROW 4%
multirow{2}*{bfseries Comportamento} & Pearson's $r$ & & & & blank & $0.094$ & $-0.125$ \
& $p$-value & & & & blank & $0.189$ & $0.080$ \

% ROW 5%
multirow{2}*{makecell{bfseries Comunicazione\ bfseries prosociale}} & Pearson's $r$ & & & & & blank & $0.069$\
& $p$-value & & & & & blank & $0.334$\

% ROW 6%
multirow{2}*{makecell{bfseries Comunicazione\ bfseries  non verbale}} & Pearson's $r$ & & & & & & blank \
& $p$-value & & & & & & blank \

bottomrule
multicolumn{8}{l}{$^* p<.05, ^{**} p<0.1, ^{***}p<.001$}
end{tabular}
caption{Correlazioni tra i fattori}
label{table:correlazione}
end{table}


end{document}