Is it possible for someone to give up their chance to go to Heaven? For example, if someone were to swear by Allah they are going to Hell (and they do so by intending to give up their right to go to Heaven), then are they destined for Hell? What if such a person repents of this and regrets this, then do they still have a chance to go to Heaven or are they destined for Hell regardless?Similarly, if someone swears by Allah that they are going to Hell if they are lying, and they are lying, then is such a person destined for Hell, even if they repent and regret their decision?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

It is not permissible to swear by supplicating against oneself for evil or for entering Hell because the Messenger of Allah said: “Do not invoke curses on yourself or on your children or on your possessions lest you should happen to do it at a moment when the supplications are accepted, and your prayer might be granted.” [Muslim]

It is necessary to repent to Allah for that. If one swears that he is going to be in Hell, then he should ask Allah for forgiveness, regret what he did, and resolve not to do that again.

What was mentioned does not mean that a Muslim will be deprived of entering Paradise or that his destiny will be in Hell.

Allah knows best.