Our sages say that a person who repents from fear is not like one who repents from love-the former converts his deliberate sins to inadvertent sins while the latter transforms them to merits. This distinction in the effect of repentance derives from a distinction in its nature.

One who repents from fear is actually nullified and subservient to G‑d; however this subservience is akin to being forced, out of fear of the Master. Accordingly, his Divine service can be described as “negative”-he strives to nullify every obstacle to Divine service. The outcome of the repentance, then, is also “negative”: the deliberateness of willful transgressions is “negated” (they are transformed to inadvertent sins).

However, one who repents out of love sanctifies himself to serve G‑d with love and desire, driven by longing to cleave to Him; he thus achieves a new existence, one of Divine attachment. The outcome of the repentance is similar-deliberate sins are transformed to a new existence: merits.

(Likkutei Sichot, vol. 14, p. 130)