The SfListView supports customizing the selection background color for the selected items by using the SfListView.SelectedItemTemplate if the background color is set to view loaded in the SfListView.ItemTemplate.
<ContentPage xmlns:syncfusion="clr-namespace:Syncfusion.ListView.XForms;assembly=Syncfusion.SfListView.XForms">
<syncfusion:SfListView x:Name="listView">
<syncfusion:SfListView.SelectedItemTemplate>
<DataTemplate>
<Grid x:Name="grid" BackgroundColor="RoyalBlue">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="1" />
</Grid.RowDefinitions>
<Label Text="{Binding SongTitle}" />
<Label Text="{Binding SongAuther}" Grid.Row="1"/>
<Frame Grid.Row="2" HasShadow="True" HeightRequest="1"/>
</Grid>
</DataTemplate>
</syncfusion:SfListView.SelectedItemTemplate>
</syncfusion:SfListView>
</ContentPage>
To know more about selection in ListView, please refer our documentationhere.