Was Jacob a heart believer when the angels met him?
No. When the angels of God met Jacob, he acknowledged them as God's host, but he was still not a heart believer. He was aware of God's workings, yet his heart had not yet been transformed into genuine faith. At that point, his recognition of God's host did not indicate heart belief.
Les explains that Jacob was aware of all these things God was doing, but he was still not a heart believer. In Genesis 32, after Jacob went on his way, the angels of God met him. When Jacob saw them, he said, "This is God's host," and he called the name of that place. Les points out that this awareness of God's activity did not mean Jacob had heart belief; he remained not a heart believer at that time.
And Jacob went on his way, and the angels of God met him.
And when Jacob saw them, he said, This is God’s host: and he called the name of that place Mahanaim.