I used RadListView in a Grid, Grid has ColumnSpacing,
for example:
<Grid
RowSpacing="1"
ColumnSpacing="1"
WidthRequest="305"
HeightRequest="303"
BackgroundColor="#FF454545">
<Grid.RowDefinitions>
<RowDefinition Height="36"/>
<RowDefinition Height="28"/>
<RowDefinition Height="82"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="152"/>
<ColumnDefinition Width="152"/>
</Grid.ColumnDefinitions>
<telerik:RadListView x:Name="listView" Grid.Row="5" Grid.ColumnSpan="2" WidthRequest="305">
<telerik:RadListView.ItemTemplate>
<DataTemplate>
<telerik:ListViewTemplateCell>
<telerik:ListViewTemplateCell.View>
<Grid BackgroundColor="Gray">
<Label Margin="10" Text="{Binding Name}" />
</Grid>
</telerik:ListViewTemplateCell.View>
</telerik:ListViewTemplateCell>
</DataTemplate>
</telerik:RadListView.ItemTemplate>
</telerik:RadListView>
</Grid>
I found the RadListView.Width is 304(ColumnDefinition plus), not 305.