Found in the books of Matthew, Mark, Luke, John, Acts, First Thessalonians and First John, the Greek adverb “alethos” meant “truly” or “certainly.” Some were “certain” Peter was one of Jesus’ disciples (Mt. 26:73Mt. 26:73
English: American Standard Version (1901) - ASV
73 And after a little while they that stood by came and said to Peter, Of a truth thou also art one of them; for thy speech maketh thee known.

WP-Bible plugin; Mk. 14:70Mk. 14:70
English: American Standard Version (1901) - ASV
70 But he again denied it. And after a little while again they that stood by said to Peter, of a truth thou art one of them; for thou art a Galilaean.

WP-Bible plugin) and a centurion said Jesus was “truly” God’s Son (Mt. 27:54Mt. 27:54
English: American Standard Version (1901) - ASV
54 Now the centurion, and they that were with him watching Jesus, when they saw the earthquake, and the things that were done, feared exceedingly, saying, Truly this was the Son of God.

WP-Bible plugin). Jesus used this term in Jn. 1:47Jn. 1:47
English: American Standard Version (1901) - ASV
47 Jesus saw Nathanael coming to him, and saith of him, Behold, an Israelite indeed, in whom is no guile!

WP-Bible plugin to affirm the sincerity of Nathanael. In Jn. 6:55Jn. 6:55
English: American Standard Version (1901) - ASV
55 For my flesh is meat indeed, and my blood is drink indeed.

WP-Bible plugin this word is translated “indeed.”