In Iran it is illegal to convert away from Islam. For a man this carries a death sentence; a woman gets life in prision.
In the civilized world, there is no punisment for converting.
The muslim world is not so kind:
The Muslim Bible commands Muslims to murder all non-Muslims:
"O Prophet! Make war against the unbelievers [all non-Muslims] and the hypocrites and be merciless against them. Their home is hell, an evil refuge indeed." (Koran, 9:73)
"When you meet the unbelievers in jihad [holy war], chop off their heads. And when you have brought them low, bind your prisoners rigorously. Then set them free or take ransom from them until the war is ended." (Koran, 47:4)
"The punishment of those who wage war against Allah and his messenger and strive after corruption in the land will be to be killed or crucified, or to have their hands and feet chopped off on opposite sides, or to be expelled out of the land. Such will be their humiliation in the world, and in the next world they will face an awful horror." (Koran, 5:33-34)
"When we decide to destroy a population, we send a definite order to them who have the good things in life and yet sin. So that Allah's word is proven true against them, then we destroy them utterly." (Koran, 17:16-17)
"In order that Allah may separate the pure from the impure, put all the impure ones [all non-Muslims] one on top of another in a heap and cast them into hell. They will have been the ones to have lost." (Koran, 8:37)
"How many were the populations we utterly destroyed because of their sins, setting up in their place other peoples." (Koran, 21:11)
"Remember Allah inspired the angels: I am with you. Give firmness to the believers. I will instill terror into the hearts of the unbelievers: you smite them above their necks and smite all their fingertips off of them." (Koran, 8:12)