How to bind HTML String to WebView?

I've got a bindable string that's populated with HTML.

    public string Description
    {
        get { return _description; }
        set
        {
            _description = value;
            OnPropertyChanged();
        }
    }

Now I'd like that string to be bound to a webview

  <WebView Source="{Binding Description}" VerticalOptions ="FillAndExpand"/>

but this isn't working. Unfortunately the Docs for WebViewSource hasn't been entered yet.

How can I bind a string of HTML to a WebView?