1) Is it true that it can be given only if the candidate is in the danger of death?
2) Is it sinful to delay baptism in order to get rid of a sinful habbit or to better know your faith?
3) Can baptism really heal sinful habits, and my tendency to doubt, anger and despair?
4) my will is very weak, can baptism make me an iron-willed person? ( like a choleric one)
5) will God give me a grace to remain innocent till death?(like sts. Dominic Savio and Therese)
6) will my prayers be granted if i make them at the moment of baptism?(like this one: Lord let me die before the first mortal sin)

1) YES. The priest is the ordinary minister of Baptism. But in case of necessity, where there is danger of death and a priest is unavailable, anyone- man, woman or child (even someone of a different religion)- can baptize validly (as long as they have the proper intention and use the proper form).

If an adult permits himself to be baptized without necessity by a layman, he would be acting illicitly but the baptism would still be valid.

2) NO. It is only sinful to delay baptism for a baby. But, for children who are at the Catechetical age (able to receive catechism instructions) , teens, and adults, baptism is delayed because they first need to receive religious instructions. They are called catechumens and usually receive instruction for 6 months and then are baptized at the Easter Vigil.

People often struggle with sinful habits for years or even a lifetime. For all you know, it could take you just as long to get rid of your sinful habits, so delaying baptism wouldn't be the wisest thing. As long as you have contrition and the desire to overcome your sinful habits, then you should still seek baptism.

3) YES. Christ instituted Baptism as the sacrament of spiritual birth (when your soul is given the new life of sanctifying grace by which you become a child of God and heir of heaven). The sacramental grace of Bapism gives you actual graces needed to live a Christian life. Furthermore, without Baptism, you cannot receive the other sacraments of the Church that also aid you in the spiritual life. For instance, you would not be able to receive the Holy Eucharist, which is spiritual food for the soul. You would not be able to go to Confession either, which gives you to the grace to better overcome your sins in the future. And you would not be able to receive Confirmation, which gives you the 7 gifts and 12 fruits of the Holy Spirit and gives you strength to fight the spiritual battle.

4) YES. See answer #3 (as long as you cooperate with the sacramental graces)

5) YES. Through Baptism and the other sacraments God will give you all the graces needed to live well the supernatural life. But, while God may give you the help, you still need to cooperate with those graces. If you cooperate with the graces God gives you, you will receive more graces. So, it is up to you whether you remain innocent until death. The sacraments only give you the tools to be holy. How well you use those tools is up to you. The saints acheived holiness through their heroic efforts.

6) MAYBE, BUT PROBABLY UNLIKELY. Whether God answers this particular prayer or not is up to Him. He answered St. Rita's prayer that her sons die before they commit the mortal sin of avenging their father's death. St. Imelda Lambertini was taken to heaven immediately after receving her First Communion (God wanted her while she was still pure and undefiled in sin). But those were out of the ordinary graces that were given. If God doesn't answer your prayer for this particular grace, it is only because He wants you to prove your love for Him and to merit your salvation by fighting the spiritual battle. In other words, He wants you to obtain heaven by working for it. Anyway, you will gain more merit and be closer to God in heaven if you've suffered and given up more in life to remain in sanctifying grace.

There are some things that make me waver. I know that God is truthful and his words are real. But in the real life his promises are not literary fulfilled... for example if you look at the Bible where Jesus says that he will give us everything we ask of the father in his name, He doesn't mean that will give us what we want even if it is harmful for us or for others, if it is against God's plans etc. etc. Or "whosoever believes in me has life everlasting" needs to be compared to other verses to tradition to dogmas and so on... An other example is " Those who come to me shall not thirst",and we know that many christians are spiritually thirsty. A catholic may die of hunger although Jesus said that he will take care of every thing ( look at the verses when he speaks about ravens of air and how God feeds them. )
So I am afraid lest the beliefe in baptismal graces falls into these categories.