If WorkSheet("wsName") Exists

A version without error-handling:

Function sheetExists(sheetToFind As String) As Boolean
    sheetExists = False
    For Each sheet In Worksheets
        If sheetToFind = sheet.name Then
            sheetExists = True
            Exit Function
        End If
    Next sheet
End Function

There's no built-in function for this.

Function SheetExists(SheetName As String, Optional wb As Excel.Workbook)
   Dim s As Excel.Worksheet
   If wb Is Nothing Then Set wb = ThisWorkbook
   On Error Resume Next
   Set s = wb.Sheets(SheetName)
   On Error GoTo 0
   SheetExists = Not s Is Nothing
End Function

also a slightly different version. i just did a appllication.sheets.count to know how many worksheets i have additionallyl. well and put a little rename in aswell

Sub insertworksheet()
    Dim worksh As Integer
    Dim worksheetexists As Boolean
    worksh = Application.Sheets.Count
    worksheetexists = False
    For x = 1 To worksh
        If Worksheets(x).Name = "ENTERWROKSHEETNAME" Then
            worksheetexists = True
            'Debug.Print worksheetexists
            Exit For
        End If
    Next x
    If worksheetexists = False Then
        Debug.Print "transformed exists"
        Worksheets.Add after:=Worksheets(Worksheets.Count)
        ActiveSheet.Name = "ENTERNAMEUWANTTHENEWONE"
    End If
End Sub