folding should never cross your mind in this spot. if villain makes a near pot size bet, u might have to take a bit of time. but id probably still call, unless he's incapable of making moves. folding to his 40 dollar bet on the river into a 210 pot may win the worst play of the year award on this forum. NEVER EVER FOLD here. try playing some lower stakes next time b/c u really don't seem like you're comfortable at the limit ur playing and u don't seem to have a concept of pot odds. villain's bet isn't really a "value bet" since it's so tiny. call, lose, and just laugh at him for not betting more.