Do not obstruct the path of Allah with suspicions!
When stories are published about brothers and sisters who embraced Islam after being from sects that were fiercely hostile to it, some comment: "Do not believe them... this is a conspiracy to infiltrate the ranks of Muslims!!" And this talk is truly a product of ignorance and an obstruction of the path of Allah! For your information, there are many among the followers of other religions—both men and women—who conceal their faith, and some who reveal it but, especially the sisters, face humiliation, beating, degradation, insults to their religion, and are prevented from wearing the hijab, praying, or fasting... particularly in this era where Islam has no strong state to protect it or shelter those who enter it... this is an era without sanctuary!
So imagine the sister who suffers all of this... who endures with patience and waits for the hour of relief... imagine when she sees from her Muslim brothers on social media accusations and doubts and the "rejection of her Islam" attributed falsely to Allah! Instead of seeing from them sincere efforts to solve the plight of these sisters...
What a betrayal this is?! And what an obstruction of the religion of Allah this is?!
As if these people have not heard the hadith of Usamah ibn Zayd, may Allah be pleased with him, when he pursued a polytheist and the polytheist, in his final moments, said: "There is no god but Allah." Usamah killed him. When he returned to Medina, the Prophet, peace and blessings be upon him, said to him: (O Usamah, did you kill him after he said: There is no god but Allah?!) Usamah replied: (O Messenger of Allah, he only said it to seek refuge.) meaning he said it out of fear, not faith. The Prophet, peace and blessings be upon him, said: (Did you kill him after he said: There is no god but Allah?!) and kept repeating it. So, could the man have truly said it to protect himself? Yes, but that is not your concern. Your concern is: whoever says there is no god but Allah and enters the religion of Islam, you must accept them and refrain from harming them. This is part of the greatness of this religion we were born into by Allah’s grace, and it is not our right to deprive others of it. Strangely, these doubters about the Islam of new converts—both male and female—may include those who, when a person dies openly denying Allah, but is a "supporter of Palestine" or a "supporter of the Syrian revolution," they try by all means to force him into the gate of Paradise! Meaning, there is no discipline in applying Allah’s rulings—neither for disbelief nor for faith!
Vigilant conduct and not disclosing secrets is an obligation, whether for a Muslim by birth or a Muslim by guidance... but to "reject" anyone’s Islam "as a precaution" is nothing but ignorance and an obstruction of the path of Allah.
Someone might say:
"Fine, suppose it later turns out that one of these 'converts' was not sincere in her Islam... why expose yourself to this? What will be your stance then?"
The answer: the same stance as Usamah, may Allah be pleased with him, if he had not killed the man and then it turned out he was not sincere and had harmed Muslims! Would the Messenger of Allah, peace and blessings be upon him, have blamed him? Never... why? Because he did what was required of him. (We only bear witness to what we know, and we are not keepers of the unseen.)
As Umar, may Allah be pleased with him, said in the narration reported by al-Bukhari: "Indeed, some people were judged by revelation during the time of the Messenger of Allah, peace and blessings be upon him, and now revelation has ceased. We now judge you only by what is apparent of your deeds. Whoever shows us good, we trust him and draw him near, and we have no concern with what is hidden in his heart—Allah will hold him accountable for that. And whoever shows us evil, we do not trust him nor believe him, even if he claims his hidden intentions are good."