Allow me to educate you a little here so that you don't remain in ignorance on this point...
Firstly, this is not a passage or subject matter that you can call upon a single word for justification or nullification. The intent of God is made fully known in that He has already made up His mind that He will bring disaster unless they repent, and if they do repent, He has already made up His mind to not bring disaster. The only way you can come to the full and complete, accurate understanding of a text is to take everything in the text into consideration. You are arguing out of a bias against the idea that you have in your mind, but that idea is based upon a false premise.
God knows everything that will ever take place, and in order to be righteous, He sets the rules. Those rules do not change. If this...then this, but if that...then that. Since He has already made the rules, it does you no good to try and play against them, which is what you have done (albeit without understanding that you have).
Your argument is void and moot. God does not "repent," nor does He change His mind. He acts according to righteousness and the righteous and just rules that He has ALREADY set. IF you die in your sins, He will sentence you to eternal fire. But if you repent, walk with Him according to His rules, and die in personal relationship with Him, then you will go to heaven. "If...then; if not...then."
Secondly, God does NOT contradict Himself, ever. Therefore, when we read that God does not repent (I Sam. 15:29), that is exactly what He means. Whenever you find an "apparent" contradiction in Scripture, it is NOT Scripture that contradicts...it is either a faulty translation of one or more texts, or it is your carnal interpretation. But God does not contradict Himself.
Hope that helps.