'Truly' in the Bible

If Cain will be avenged seven times, truly Lamech seventy-seven times."

Now if you will deal kindly and truly with my master, tell me. If not, tell me, that I may turn to the right hand, or to the left."

The time drew near that Israel must die, and he called his son Joseph, and said to him, "If now I have found favor in your sight, please put your hand under my thigh, and deal kindly and truly with me. Please don't bury me in Egypt,