.NET (Core and Framework)

Hello 
I have been programming for something like 3 years in VBA - Excel and trying to move to VB.Net, The reason I want to move to .Net is basically because of security issues (I really enjoy programming to help excel users) and because I believe for sure that using .Net framework is a more robust platform and I will be able to keep working with excel users and also start programming new things.
I need some clarification about .Net Framework security. I have been searching the web the last week reading and understanding how I can protect connection strings and realize (I think) that the best way is by encrypting the app.config connectionstring section. 
But now I am really frustrated because I made a very simple test and then I myself tried to hack my application and it was very, very simple to reveal the connection strings. 
The reason I am asking is because may be I am misunderstanding something and I want to clarify if it is really that simple to hack the connection strings? And obviously get advice if I am doing something wrong…? 
If I am right…, let me ask you if there is a way to really protect a connection string from being read in a windows application that will be in the user computer? 
I also think and to encrypt a simple .xml (Not an app.config) with the connection strings but this will be useless because in order my app can decrypt the .xml, the app needs to have the decryption sub inside the .exe or a .dll and with any decomplier a hacker can read the code and copy the decrypt sub to decrypt the .xml.
I have also read there are a lot of code ofuscators but they are expensive and at this point I only want to know if it possible to really protect a connection string.
Please HELP… I am getting mad trying to figure it out!!! 
Let me explain the test I did:
1.- Create a windows test app with 2 buttons and 1 app.config
App.config:
<?xml version='1.0' encoding='utf-8'?>
<configuration>
<connectionStrings>
  <add name ="sourcepath"  connectionString ="valid url path"/>
  <add name ="finalpath"  connectionString ="valid desktop path"/>
</connectionStrings>
</configuration>


Button 1:
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
  Try
      Dim path As String =ConfigurationManager.ConnectionStrings("sourcepath").ConnectionString
      Dim path1 As String = ConfigurationManager.ConnectionStrings("finalpath").ConnectionString
      ' Download file from web server to my desktop
      Dim fileReader As New WebClient()
      fileReader.DownloadFile(path, path1)
  Catch ex As Exception
      MsgBox(ex.Message)
  End Try
End Sub

Button 2: I just copy ToggleConfigEncryption sub from http://msdn.microsoft.com
Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        Call ToggleConfigEncryption("WindowsApplication4.exe"
End Sub

Sub ToggleConfigEncryption(ByVal exeConfigName As String)
        ' Takes the executable file name without the .config extension.
        Try
            ' Open the configuration file and retrieve 
            ' the connectionStrings section.
            Dim config As Configuration = ConfigurationManager. _
                OpenExeConfiguration(exeConfigName)

            Dim section As ConnectionStringsSection = DirectCast( _
                config.GetSection("connectionStrings"), ConnectionStringsSection)

            If section.SectionInformation.IsProtected Then
                ' Remove encryption.
                section.SectionInformation.UnprotectSection()
            Else
                ' Encrypt the section.
                section.SectionInformation.ProtectSection( _
                  "DataProtectionConfigurationProvider")
            End If

            ' Save the current configuration.
            config.Save()

        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
End Sub

2.- Run app, press button 2 to encrypt app.config connectionstrings section, press button 1 to download file, open app.config with notepad and verify the section is encrypted. So far, so good!!!
Now to hack my own app did the following.
1.- Download JustDecomile a free .Net decoder from internet
2.- Open my app with Just Decompile and I was able to read from button 1:
Dim path As String =ConfigurationManager.ConnectionStrings("sourcepath").ConnectionString
Dim path1 As String = ConfigurationManager.ConnectionStrings("finalpath").ConnectionString

3.- create a new app with following code: (I just copy paste from Just Decompile to new app and add msgbox line)
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
  Dim path As String = ConfigurationManager.ConnectionStrings("sourcepath").ConnectionString
  Dim path1 As String = ConfigurationManager.ConnectionStrings("finalpath").ConnectionString
  MsgBox(path & " " & path1)
End Sub

4.- Compile the new application.
5.- Copy the new application to test app directory
6.- Rename the new application with same name as test app (Maybe not necessary)
7.- Run the new app and I got a message box with the connection strings in 100% readable text!!!

Private _matrix as double(,)

Public Function CopyToArray() as Double(,)
    Return Me._matrix.Clone()
End Fucntion

Public Function Copy() As Matrix
    Return New Matrix(Me.CopyToArray())
End Function

Public Sub New(ByVal array As Double(,))
    Me._matrix = array
End Sub

<asp:TemplateField HeaderText="Percentages">
    <ItemTemplate>
        <asp:Label ID="PERCSIT" runat="server"></asp:Label>
    </ItemTemplate>
    <EditItemTemplate>
        <asp:TextBox ID="PERCS" runat="server" Text='Even geduld a.u.b.'></asp:TextBox>
    </EditItemTemplate>
    <ControlStyle BackColor="#00CC00" Width="35px" />
</asp:TemplateField>

''' <summary>
''' Gets the upper bound of the specified dimension in the matrix
''' </summary>
''' <param name="dimension">A zero based dimension of the matrix. Must be zero or one since the a Matrix is two dimensional</param>
''' <value></value>
''' <returns>The upper bound of the specified dimension</returns>
''' <exception cref="IndexOutOfRangeException">This exception is thrown if the specified <paramref name="dimension"/><c> is less than zero or exceeds one, since the a Matrix is two dimensional</c></exception>
''' <remarks></remarks>
Public ReadOnly Property UpperBound(ByVal dimension As Integer) As Integer
    Get
        Try
            Return Me._matrix.GetUpperBound(dimension)
        Catch inex As IndexOutOfRangeException
            Throw New IndexOutOfRangeException("The dimension you specified is out of range for this matrix object. Matrix objects have only two dimensions, 0 and 1. See the inner exception for more detail.", inex)
        Catch ex As Exception
            Throw
        End Try
    End Get
End Property