[jesse8888]

This is a situation where having specific reads on specific opponents is very, very important. In general if someone bets into the world on the flop, I find it's a pretty safe bet that they don't have trips. However, there are some opponents (myself included) who will often just fire into 3 to 5 callers with trips and hope to get raised. If you have a read on your opponent in this case, it tends to help quite a bit.

Also, it's important to note what rank the pair is. Even the worst players are less likely play 2s or 3s than Js or Ts.