# Truly I say to you
"I tell you the truth." This phrase adds emphasis to what Jesus says next.
# if he does not doubt in his heart but believes
Here "heart" is a metonym for a person's mind or inner being. Alternate translation: "if he truly believes in his heart" or "if he does not doubt but believes" (See: [[rc://en/ta/man/translate/figs-metonymy]])
# God will do
"God will make happen"