Castaignos has twin focus with Twente
The 19-year-old signed a four-year deal with Steve McClaren's side after failing to make an impact with Serie A club Inter Milan, making just six league starts last season.
"I opted for the security to be able to play again," said Castaignos. "I've always learned: when you have a chance, you should seize with both hands.
"Eventually I noticed that Inter do not have much confidence in me. Then it is very simple, you should go somewhere else for your chance. At Inter, I trained and played with the best of Europe. With Twente, I play for the championship."
Castaignos began his professional career with Feyenoord and, after scoring 15 league goals in 37 matches in Rotterdam, joined Inter for €3million in March 2011.