No system can fully present a Trump like from winning.  Netherlands and Austria both use PR and in both countries their far right Trump like leader is leading in the polls.  True they have well under 50% so the other parties could form a coalition to keep them out but in the case of the Netherlands its a long standing tradition the party that gets the most votes supplies the PM while in Austria the far right FPO is at 35% and finding enough common ground with the remaining parties might be a challenge.  In the UK, UKIP got 13% of the popular vote but only 1 seat so instead of having a Conservative-UKIP coalition which would be quite right wing you have a centre-right Conservative government so in that case FTFP works.