After … said this is literally “having said these things,” the same transitional formula used in 7.9; 9.6; 11.28,43; and 18.1.

He was deeply troubled is literally “he was troubled in spirit” (see comments at 12.27). In 14.1,27, the verb “to be troubled” is used of the disciples. Such an expression as deeply troubled may be expressed best by a figurative phrase, for example, “his thoughts made him suffer” or “he was pained in his heart” or “his liver quivered.”

Declared openly is literally “he testified and said,” reflecting the redundancy of Semitic Greek style. The verb “to testify” was first discussed in 1.7. New English Bible translates “Jesus exclaimed,” and Jerusalem Bible “declared.” The language of New American Bible is rather formal: “He went on to give his testimony.” An equivalent of declared openly may be “said clearly” or “said without hiding anything.”

I am telling you the truth is the same expression used in verses 16 and 20. See at 1.51.

The verb “to betray” first appears in 6.64.

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .