Just to clarify what I want to find out:

Can I and my unmarried girlfriend (who does not have the same family name as me) check in to a hotel and share the same room?

And I don't want to go to Spain or Italy.

The reason I am looking at Qatar is also that it's approx 6 hours non-stop flying time from BKK and from where I am right now.

If she were to visit me or I go to BKK it would take most of a day each way and we only have 4-5 days to spend.