If as Rick suggests you are confusing it with a Regex comparison you would
have to do something like this to test if the pattern exists in the testdata.
string testdata = "ABC Properitory Limited XYZ";
string pattern = @".*Properitory\s+Limited.*";
Match match = Regex.Match(testdata, pattern);
if (match.Success)
{
Console.WriteLine("Pattern exists in str1");
}
else
{
Console.WriteLine("Pattern does not found in str1");
}