Anyone know how to deal with memory leaks?

My C++ variable has a memory leak and its causing the game to crash after a couple of restarts. Here is the code:

Custom Function()
{

UE_LOG(LogTemp, Log, TEXT(FStage: %d), Stage);
ensureMsgf(Stage >= 0 && Stage < 10, TEXT(Stage is out of expected bounds: %d), Stage);
Stage++;
}

Constructor()
{
Stage = 0
}

Somehow Stage is breaking and causing memory leaks. Anyone know how to fix this?