Here function that check if it RTL:
// Method to check if a string contains RTL characters
static bool ContainsRTLCharacters(string text)
{
const int RTLCharacterStart = 0x0590;
const int RTLCharacterEnd = 0x08FF;
var regex = new Regex(@"[\u0590-\u08FF\u200F\u202A-\u202E\u2066-\u2069]");
return regex.IsMatch(text);
}