He trusts in God can be rendered by “He believes God will be with him (or, take care of him)” or “He depends on God to be with him.”

He trusts in God; let God deliver him now, if he desires him echoes Psalm 22.8, as the shaking of heads (verse 39) hints of Psalm 22.7. Commentators also note the similarity between the scene here and the philosophy expressed in the Wisdom of Solomon 2.6-20 (especially verses 17-20). Let God deliver him now, if he desires him is effectively restructured in Good News Translation: “let us see if God wants to save him now.” The order may be reversed: “If God wants to save him, let him do that now.”

Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on the Gospel of Matthew. (UBS Handbook Series). New York: UBS, 1988. For this and other handbooks for translators see here .