...the yetzer hara especially overwhelms a Jew so that he won't do teshuvah because it knows how great is the power of teshuvah and therefore it stands itself before a Jew as if he can't do teshuvah.
Because he has already done teshuvah so many times and he wasn't able to keep up his teshuvah and he went back to whatever he was and what is the point now if he does teshuvah again?
And [the yeter hara] paints him a picture of how his transgression is too great to bear and teshuvah will not be effective for him.
"Shuva Yisrael ad Hashem Elokecha — Return in repentance, Jew, until Hashem Your God."
A part of Hashem is always with you.
Likewise, a Jew is one part of Above, in the words of Netivot Shalom. Therefore:
And in any case, there is no place for all these cheshbonot (considerations) that hold him back from doing teshuvah....All the natural chesbonot do not apply to a Jew, that he has done teshuvah so many times, and it hasn't been effective for him and what is the point of him doing teshuvah again? And anyway, what with his transgression being too great to bear.
All these cheshbonot do not grasp the elevated level of a Jew that he is one part of Above.
...and when a Jew sins — even intentionally — including the times he cannot overcome his inclination, his heart rips within him at the moment of the deed due to the greatness of his distance from Hashem Yitbarach...in a sin like this, that even at the hour of sin, Hashem his God is with him.
Netivot Shalom goes on to explain that if even at the time of a sin, you can remember Hashem and think in your heart "Behold, I'm disconnecting myself from the root" — And Hashem? He'll fulfill the verse: "Lo hibit aven b'Yaakov — He does not look at evil in Yaakov" (Badmidbar 23:21).
Simply put, Hashem considers all sin as stumbling. You're not evil or hopeless, you just tripped up. Your yetzer overcame you.
YOU are GOOD. You are holy.
For a Jew is one part from Above and his essence is that he wants only good — only the evil inclination provokes us.
He goes on to explain that if we could really feel how much Hashem loves us, we could connect to him and not WANT to sin out of our great love for Him.
The main part of teshuvah, states Netivot Shalom, is to return to Hashem and not feel yourself so far or disconnected from Hashem. Just return to him and feel that Hashem is YOUR God.
Because He really is.