How to counter Bel'Veth
Let us take a look on how to beat Bel'Veth. We will look at champions who are strong against Bel'Veth and who are weak against Bel'Veth. Use win rate, gold difference and creep score difference at minute 10 to find the best 
Jungle champion who counters Bel'Veth. You can already win in champion select with the right counters for Bel'Veth. If you want to know how to counter Bel'Veth then you need to take into account the best picks vs Bel'Veth and the worst picks vs Bel'Veth. This Bel'Veth counter data is based on matches played by Pros on patch 14.23 and previous ones. It is important to see whether Pros counter picked Bel'Veth or whether they played as Bel'Veth.
Champions used by Pros to counter pick Bel'Veth
Looking at the matches from Pros (see table Pros counter picked Bel'Veth) we can see that they picked 
Lee Sin most often to counter pick Bel'Veth. The matchup Lee Sin vs Bel'Veth occured 32 times. Bel'Veth has 16 wins and 16 losses in this matchup. Learn how to counter pick Lee Sin to get another perspective on the data.
Lane outcome for Bel'Veth
When looking at Bel'Veth counters you will notice that win rates alone are not conclusional. Therefore we provide an overview (see table Lane Outcome) where you can see the lane outcome of Pros who played Bel'Veth. The lane outcome of Bel'Veth consists of three outcomes: Win, Loss or Draw. Let's take a look of Bel'Veth lane and match outcome for specific matchups. Considering the lane outcome and the match outcome of a specific matchup, might enable you to find the right counter for Bel'Veth.
Conclusion
Analyze the available data and learn how to beat Bel'Veth. To master Bel'Veth take also a look on Bel'Veth builds and runes for Bel'Veth. Good luck, Summoner!