As the seat of the energy of the divine Spirit (πνεῦμα see on Rom 8:4); mediating the personal life (of the soul ψυχή, see on Rom 11:3), which is conditioned by the Spirit. It is not the affections as distinguished from the intellect. Believing with the heart is in contrast with oral confession, not with intellectual belief. “Believing is a mode of thinking not of feeling. It is that particular mode of thinking that is guided to its object by the testimony of another, or by some kind of inter-mediation. It is not intuitive” (Morison).
Man believeth (πιστεύεται)
The verb is used impersonally. Lit., it is believed. Believing takes place.
Confession is made (ὁμολογεῖται)
Also impersonal. It is confessed. “Confession is just faith turned from its obverse side to its reverse ... When faith comes forth from its silence to announce itself, and to proclaim the glory and the grace of the Lord, its voice is confession” (Morison).