Вы должны использовать Grid
вместо StackPanel
.
Как то так,
<Grid Width="400" Margin="40,0">
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="Auto" />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<TextBlock Text="dfgdfdgdfgfdgdfg" Foreground="AntiqueWhite" FontSize="30" TextWrapping="Wrap"/>
<TextBlock Text=" vs " FontSize="30" Foreground="White" TextWrapping="Wrap" Grid.Column="1"/>
<TextBlock Text="Indiaafda (text)" Foreground="Bisque" FontSize="30" TextWrapping="Wrap" Grid.Column="2"/>
</Grid>
Я, вероятно, перепроектирую все это, чтобы быть примерно таким,
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid d:LayoutOverrides="Height" Margin="40,0">
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="Auto" />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<TextBlock Text="dfgdfdgdfgfdgdfg" Foreground="AntiqueWhite" FontSize="30" TextWrapping="Wrap"/>
<TextBlock Text=" vs " FontSize="30" Foreground="White" TextWrapping="Wrap" Grid.Column="1" VerticalAlignment="Center" HorizontalAlignment="Center"/>
<TextBlock Text="Indiaafda (text)" Foreground="Bisque" FontSize="30" TextWrapping="Wrap" Grid.Column="2"/>
</Grid>
<Grid Grid.Row="1">
<TextBlock HorizontalAlignment="Center" TextWrapping="Wrap" Text="where other stuff goes" VerticalAlignment="Center"/>
</Grid>
</Grid>
UPDATE
<Grid VerticalAlignment="Top" Margin="40,0">
<TextBlock Foreground="AntiqueWhite" FontSize="30" TextWrapping="Wrap">
<Run Text="south africa"/>
<Run Text="vs"/>
<Run Text="windows phone"/>
</TextBlock>
</Grid>