The Bible says that without repentance there is no salvation.

As the Lord Jesus Christ says:  "except ye repent, ye shall all likewise perish"  (Luke 13:3)
God commands that we repent.  "Jesus came into Galilee, preaching the gospel of the kingdom of God, And saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and believe the gospel."  (Mark 1:14, 15)  Repentance requires obedience and action on our part, it is not simply a mental thing.  "Then hath God also to the Gentiles granted repentance unto life."  (Acts 11:18)  If you want to repentance, pray for it (and start obeying and repenting in what you understand of the scriptures).  You may know the definition intellectually, but not have experienced it and thus still be unrepentant.  Repentance in one's life is Spirit illuminated.  Repentance is not simply believing that I was born with a sin nature, or a turning from the outward manifestations of sin, but it is the inward Spirit illuminated flash of realization that Self is the problem and that it is exceedingly sinful and sitting on God's throne in my heart.  It is the denial of that Self that is repentance.  "If any man will come after me, let him deny himself, and take up his cross daily, and follow me.

Here is what John Bunyan (Pilgrim’s Progress) wrote about repentance.  It shows how easy it is to repent the wrong way:

There is a repentance that will not save, a repentance to be repented of; and a repentance to salvation, not to be repented of. (2 Cor 7:10) Yet so great a similitude and likeness there is betwixt the one and the other, that most times the wrong is taken for the right, and through this mistake professors perish. As, (1.) In saving repentance there will be an acknowledgment of sin; and one that hath the other repentance may acknowledge his sins also. (Matt 27:4) (2.) In saving repentance there is a crying out under sin; but one that hath the other repentance may cry out under sin also. (Gen 4:13) (3.) In saving repentance there will be humiliation for sin; and one that hath the other repentance may humble himself also. (1 Kings 21:29) (4.) Saving repentance is attended with self-loathing; but he that hath the other repentance may have loathing of sin too; a loathing of sin, because it is sin, that he cannot have; but a loathing of sin, because it is offensive to him, that he may have. The dog doth not loath that which troubleth his stomach because it is there, but because it troubleth him; when it has done troubling of him, he can turn to it again, and lick it up as before it troubled him. (2 Peter 2:22) (5.) Saving repentance is attended with prayers and tears; but he that hath none but the other repentance, may have prayers and tears also. (Gen 27:34,35, Heb 12:16,17) (6.) In saving repentance there is fear and reverence of the Word and ministers that bring it; but this may be also where there is none but the repentance that is not saving; for Herod feared John, knowing that he was a just man and holy, and observed him; when he heard him, he did many things, and heard him gladly. (Mark 6:20) (7.) Saving repentance makes a man’s heart very tender of doing anything against the Word of God. But Balaam could say, “If Balak would give me his house full of silver and gold, I cannot go beyond the commandment of the Lord.” (Num 24:13)

Behold, then, how far a man may go in repentance, and yet be short of that which is called, “Repentance unto salvation, not to be repented of.” (a.) He may be awakened; (b.) He may acknowledge his sin; (c.) He may cry out under the burden of sin; (d.) He may have humility for it; (e.) He may loath it; (f.) May have prayers and tears against it; (g.) may delight to do many things of God; (h.) May be afraid of sinning against him—and, after all this, may perish, for want of saving repentance.

The entire sermon is edifying: