His character is such that he is highly calculative and very doubtful.
He also thinks things in a long-term, and always acts after considering the worst case scenario.
He is quite competitive, but does not take part in a battle he doesn't have a chance of winning. He is a logical realist.
ご質問ありがとうございます。
"His character is such that he is highly calculative and very doubtful."＝「彼の性格は計算高く、とても疑い深いです。」
"He also thinks things in a long-term,"＝「彼は物事を長期的に考え、」
"and always acts after considering the worst case scenario."＝「そして、常に最悪のシナリオを考慮してから行動します。」
"He is quite competitive,"＝「彼はかなり競争心があります」
"but does not take part in a battle he doesn't have a chance of winning."=「ただ、勝ち目のない戦いには参加しません。」
"He is a logical realist."＝「彼は論理的なリアリストです。」
ご参考に。
アメリカ合衆国 
