I used _tabularx _package. Additional definitions:

    \usepackage{array}
    \newcolumntype{L}{>{\raggedright\arraybackslash}X} % left multiline alignment
    \newcolumntype{R}{>{\raggedleft\arraybackslash}X}  % right multiline alignment

Table:


    \begin{tabularx}{\textwidth}{@{}p{0.8\linewidth} R}
     Text, aligned to the left, without margin \newline
     Tex in the same cell on the next line   
     &                                          % next column delimiter
     Text aligned to the right \newline second line
    \end{tabularx}

Here we have one columt with 80% width and one column with right alignment @{} is required to suppress left margin in the first column.

Results: