Check if worksheet exists by name - vba

Question

I am wanting to validate if a worksheet exists, and if not then ask the user to enter select a sheet from those that exist. Looking over the information on this previous post i came up with a function that returns a boolean and then I will prompt if the result is false.
I am having an issue where the custom sheet names I have entered return false, but the default "Sheet1"... return true. Looking over the object model I do not see one listed for Worksheets.Name.Value and looking at the project explorer I see that the sheets are listed as `Sheet 1 (Macro Variables).
How do I reference the name of the sheet in parenthesis so that my function will work, or if not possible using sheet names, is there a better solution?
Here is my code
Sub TestBed()
Dim wb As Workbook, test As Boolean, debugStr As String, wsNames() As String
Set wb = ThisWorkbook
Debug.Print "List of sheets in this workbook"
For i = 1 To wb.Worksheets.count
ReDim Preserve wsNames(i - 1)
wsNames(i - 1) = wb.Worksheets(i).Name
debugStr = debugStr & wsNames(i - 1) & " | "
Next i
Debug.Print debugStr
debugStr = ""
For i = LBound(wsNames) To UBound(wsNames)
test = ValidateWorksheetExists(wsNames(i), wb)
debugStr = debugStr & wsNames(i) & " = " & test & " | "
Next i
Debug.Print debugStr
End Sub
Function ValidateWorksheetExists(sName As String, Optional wb As Workbook) As Boolean
If wb Is Nothing Then Set wb = ThisWorkbook
With wb
For i = 1 To .Worksheets.count
If wb.Worksheets(i).Name = sName Then
ValidateWorksheetExists = True
Else
ValidateWorksheetExists = False
End If
Next i
End With
End Function

Answer 1

You need to exit the function right after:
ValidateWorksheetExists = True
Otherwise the next iteration of i will set it to False again.
(there may be other errors)

Answer 2

Although a Boolean variable (err function in this case) defaults to False when declared, it's good practice to be explicit... and since ValidateWorksheetExists starts out as False, there's no need to again set it to False. Doing so reverts a possible True state that was set on a prior iteration of 'i'
Function ValidateWorksheetExists(sName As String, Optional wb As Workbook) As Boolean
If wb Is Nothing Then Set wb = ThisWorkbook
ValidateWorksheetExists = False
With wb
For i = 1 To .Worksheets.count
If wb.Worksheets(i).Name = sName Then
ValidateWorksheetExists = True
End If
Next i
End With
End Function