Allah says in Glorious Quran:
“She said: ‘My Lord! Verily, I have wronged myself, and I submit (in Islam, together with Sulaymaan (Solomon), to Allah, the Lord of the ‘Aalameen (mankind, jinn and all that exists)”
From this verse we understand that prophet Sulaiman (AS) did not force Queen of Sheeba (Bilquees) to become Muslim, rather she accepted it out of her belief in the Islam. She stated that she was the one who was wrong and had wronged herself by worshipping to the idols and submitted to the religion of Allah with Sulaiman (AS). If she had been forced to become Muslim, she would not have said that.
With regard to the words of the Prophet of Allah Sulaymaan (peace be upon him), “Go back to them. We verily shall come to them with hosts that they cannot resist, and we shall drive them out from there in disgrace, and they will be abased”
[an-Naml 27:37] This comes under the heading of Jihad which is necessary to spread Islam. It does not have anything to do with forcing someone into Islam rather the message of true religion should reach everyone. Jihad was only prescribed so that the word of Allah might be supreme, and so as to take away the authority of kingdoms that stand between the people and the religion of Allah.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
Jihad of the Muslims against the disbelievers is not for the purpose of making them become Muslim. Allah, may He be glorified, says (interpretation of the meaning): “There is no compulsion in religion” [al-Baqarah 2:256]. Rather jihad is so that the word of Allah may be supreme, and so that dominance may belong to the religion of Islam.
From Majmoo‘ Fataawa wa Rasaa’il al-‘Uthaymeen (25/303).
The Queen of Sheeba – Bilquees acknowledge that she had wronged herself with her disbelief and accepted Islam when she was content with its truth. She was not forced to do so.