Translation:Something old, something new, something borrowed, something blue.
Thank you; I was going to ask the same question. By the way, the Dutch expression would read better if the "ouds" and "nieuws" were swapped (but I know it's this way because the English is).
Traditionally these are things a bride should have with her when she gets married in the UK. I don't know if it's a tradition in NL
At least in English, it is a list of things that a bride would traditionally wear at her wedding. I don't know if the Dutch have the same traditional as well or not.
After an indefinite pronoun (iets, niets, allerlei, wat, veel, weinig, meer, minder, genoeg), an adjective gets an -s ending.
This is a remnant from the time when Dutch had cases: it's a genitive form.
More information (in Dutch): http://taaladvies.net/taal/advies/vraag/1317/