stina64 wrote:
Please let me know how to remove this trojan in a safe way...
I overlooked that question. Assuming the Windows Trojan arrived in an email attachment (that's the usual way) all you need to do is to delete the email in the usual manner. But even if you did not do that, it cannot harm your Mac.
Never permit "Bitdefender" or similarly ill-conceived apps do that. From what you wrote it tried and failed, but if it had managed to remove, isolate, "quarantine" or otherwise interfere with Mail, the result can easily be a corrupted and useless Mail account. That's a far greater threat than the mythical Mac "virus", and one reason among many for characterizing those apps as garbage. Get rid of it. Never install it, or anything like it, on a Mac.