Push on the turn!

The reason why this is a very difficult decision is becuase, what hand is going AI that he's beating?

A bluff or a flopped flush that just can't let go on the river (Another word for bluff)

The pots pretty big on the river, 4:1 to make the call but I'm almost certain you're beat. The board is scary enough for someone to really try and bluff at like he did, but I don't think they're doing it 1 in 5 times.

(He can't have the second nut flush becuase you have the Q as well.)

-'rilla