Is the feeling of guilt sufficient for repentance and its conditions?

Question:
Abu Sami says: Shaykh Salih, is feeling guilty sufficient for repentance? Is repentance accepted in that case? And what are its conditions?

Answer:
Repentance and seeking forgiveness are necessary. So seek forgiveness from Him, and seek forgiveness for your sins. One must seek forgiveness based on belief and with the presence of the heart; it is not sufficient to merely feel the need for forgiveness without uttering it, nor is it sufficient for it to pass over the tongue without the presence of the heart. Yes. He asks about a book, Shaykh (may Allah preserve you).