How will you delight in Hashem?
Rashi: Enjoy delicacies, amidst reliance on Hashem. Metzudas David - He will give all that you request, even delicacies.
Radak #1: If you do what I commanded you, you will find pleasure in all that you desire, and He will give all that you request. "V'His'aneg" is a command, just like "u'Mus ba'Har" (Devarim 32:50) is in place of "Tamus".
Radak #2: You will rejoice and feel pleasure in serving Hashem, and He will fulfill your desire.
Malbim: Your pleasure will be of the Nefesh, in Hashem - unlike Resha'im, whose Nefashos are sad, for they are far from what will return [joy] to them.
Why does it say "He will give to you your heart's request"?
Refer to 37:4:1:1-3.
Malbim: Evildoers never find their hearts' request - one who has 100, he seeks 200. One who trusts in Hashem, He will give to you your heart's request.
