betting for value

[Wacken]

please tell my if my idea is correct.

You flop a nut flush draw with 4 players still in. With 4 players, it is correct to do a bet for value. However suppose the flop are all low cards, there is no reasonable str8 posibility and 2 people will fold after your bet. Making them fold will probably not drastically improve your winning chances here. If you don't get the flush, you might have the best hand, but chances are not great, out of 4 players, the one caller is pretty likely to have a better hand than that, espescially if you have a low kicker.
Now instead of getting more money in the pot, you scared out potential bets for the turn and river.

I would guess in this situation this value bet is -EV. Am i correct that you should only make a value bet if you expect most or everyone to call? (or expect everyone to fold instead of all but one)