Hi There
I find Beirut to be as safe as any big city and my family visit here regularly! From time to time, they have a few demonstrations which can occasionally get out of hand but that can happen anywhere nowadays and they are over within hours.! I would not listen to the opinions of people who have never been to Lebanon, especially in the last 2 years.Â
Like every country, there are risky areas but you would not go there in your own country so it is a no brainer!
Hope this is of some help to you and your girlfriend.
In the meantime, take care!
Regards
Anna64;)