The English language didn't even exist when Jesus was here on earth, and even if it had existed, Jesus would have had no reason to use an English word like "believe", as His Hebrew-speaking hearers would not have understood. Anyway, the New Testament was originally written in Greek, so we don't know what Aramaic or Hebrew word Jesus actually spoke that was written in the Greek of the New Testament as "pisteuo" and translated into English as "believe."
I think there is a danger when using so-called red letter Bibles (where the words of Jesus are printed in red. Such Bibles can give the wrong idea that the words that actually came from the mouth of Jesus Christ are more important than the rest of the Bible. The whole Bible is God's word, and is inspired, or "breathed out" by Him.