People regardless of religion want to be saved.

If people know religion will lead to their downfall, will they continue to remain in that religion?

The answer is no.

Many Islam apologists say Christians must be converted to Islam if they want to be saved.

Islam apologists think of Christians as polytheists. They do not worship one God.

According to their Qur’an, anyone who worships other gods will go to Hell and this is not forgivable.  

” Verily, Allah forgives not that partners should be set up with him in worship, but He forgives except that (anything else) to whom He pleases, and whoever sets up partners with Allah in worship, he has indeed invented a tremendous sin.”(Surah An-Nia 4:48)

Numerous beautiful Islamic poems and moving prayers described Muslims’ hope for Muhammad’s intercession to be saved.

For example, Ibn Khaldun, the great North African philosopher, asked the prophet Muhammad, “Grant me by your intercession, for which I hope, a beautiful page instead of my ugly sins!” Another Muslim thinker exhorted his hearers by these words: “If a man brings on the Day of Resurrection as many good works as those of all the people in the world and does not bring with them the calling down of blessing on the Prophet, his good works are returned to him, unacceptable.”

Can Muhammad ensure his salvation?

The Quran states Muhammad was not sure whether Allah would save him:

Or do they say, ‘He has forged it’? Say: ‘If I have forged it, you have no power to help me against Allah. He knows very well what you are pressing upon; He suffices as a witness between me and you; He is the All-forgiving, the All-compassionate.’ Say: ‘I am not an innovation among the Messengers, and I know not what shall be done with me or with you. I only follow what is revealed to me; I am only a clear warner.’ S. 46:8-9 Meccan

Qur’an said prior to entering the garden, Muslims will be in hell for some time. 

Surah 3:185 “Every soul tastes the death, and surely you will only receive your wages on the day of resurrection. So whoever is removed FROM THE FIRE AND ENTERS THE GARDEN, so indeed he becomes triumphant. And what is the life of this world except the enjoyment of the proud?”

Muhammad said in the Hadith:

 “I swear by who holds my soul in his hand (Allah), my people will split to SEVENTY-THREE denominations, one will be in the garden and SEVENTY-TWO in fire (hell)…”

Muhammad did not know if he will make it to the Garden or not. He said unless Allah covers him with his mercy he will be in hell.

There is no guarantee of salvation in Islam. From the start of Islam, nearly all Muslims were fearful of their eternal destiny.  Al-Ghazali said:

I got this Book from Answering Islam. The Crescent in Light of the Cross, written by a former Muslim, Abdul Saleeb.

Yet all the fathers used to refrain from giving a definite reply concerning belief, and were extremely careful not to commit themselves. In this connection Sufyan al-Thawri said, “He who says, ‘I am a believer in the sight of God,’ is a liar; and he who says ‘I am really a believer,’ is an innovator….” Once upon a time Hassan (al-Basri) was asked, “Art thou a believer?” To which he replied, “If it be the will of God.” Thereupon he was told, “0 Abu Sasaying id, why do you qualify your belief?” He answered and said, “I fear ‘yes,’ and then God will say, ‘Thou hast lied Hassan.’ Then 1 shall rightly merit His punishment….” Alqamah was once asked “Are you a believer?” To which he replied, “I do hope so. If it be the will of God.” 77