Honesty in Repentance

There must be truthfulness in repentance (Tawbah); meaning if a person repents to Allah, he leaves the sin. As for someone who repents by speech, and his heart is occupied with committing the sin, or leaving an obligatory act, or he repents to Allah by speech and his limbs insist on committing the sin; then his repentance will not benefit him. Rather it is very similar to mockery of Allah, the Almighty. How do you say, "I repent to Allah from a sin" and you are insisting on it?! Or you say, "I repent to Allah from a sin" and you are determined to commit it? If a person treats a human being like himself in this manner he would say, "he ridicules and mocks me, how does he deny it in front of me whilst he is involved in it?" So how about the Rabb of Alamin (mankind, jinn and all that exists)?!