re-vey-yay
Here's a breakdown:
* re: Like the "re" in "red," but slightly shorter.
* vey: Like the "vey" in "they," but with a slight "eh" sound at the end.
* yay: Like the "yay" in "say," but slightly shorter.
It's important to remember that French pronunciation can be tricky, and there are often subtle differences in how sounds are pronounced. But this should give you a good starting point for pronouncing "réveiller."