Safe town, Ljubljana
Ljubljana felt like a very safe city, especially for its size. The people are very friendly and honest for the most part. You should have no problems with the taxi drivers, and I even felt safe walking about at night outside the busy city centre. I didn't even see a single beggar, although they do exist. The police aren't over officious either. For example, while it is illegal to jay walk, they didn't seem to stop people from doing it right under their noses.
Ljubljana is probably one of the safest places I have been to and it feels very safe. Then again crime takes place in Ljubljana also, so be prudent, don't walk desolate dark streets or parks alone during the night, take care of your valuables... same precautions like anywhere.
Ljubljana, being a lot smaller than most capital cities is a lot safer than they are. Apart from at the bus station where you should be on your guard against pickpockets - as a traveller you stick out quite conspicuously you should not have a lot of problems. I would simply advise erring on the side of caution - not been too showy of possessions.
snap taken from the castle over the city ....looks nice and larger than i guess at first sight..
by the way the castle....mmm i didnt like so much ..its not like spanish or french castles ..it looks like a village with houses inside it-.. its just 10-15 min walking up or a touristic railway that goes up in 5 min ....and i dont know how much it cost
Ljubljana and Slovenia in general is I think very safe and easygoing . My only suggestion is an obvious one, just in case you may have relaxed too much, which is to take care around the bus station and look out for pickpockets - as you would anywhere really.