"Les robes des femmes"
There are lots of useful videos, concerning French pronunciation on youtube. Though as a very general rule, most constants at the end of the word in French are not pronounced, hence why you need to listen to the article to consider if it is plural or not. However I seriously recommend you look up French pronunciation, as it is quite different to English. This is a good comprehensive lesson on the subject: https://www.youtube.com/watch?v=ckzM6-Ee7wU
It would not be "Le robe", because "robe" is feminine. It would be "La robe", which sounds quite different than "Les robes".
If it were a masculine noun, you can tell the difference between "Le" and "Les" because they sound different. See my other comment farther up to see what I'm talking about.