بمؤمنين

Appears 6 times in the Quran. (Root: امن)

11:53 قَالُواْ يَا هُودُ مَا جِئْتَنَا بِبَيِّنَةٍ وَمَا نَحْنُ بِتَارِكِي آلِهَتِنَا عَن قَوْلِكَ وَمَا نَحْنُ لَكَ بِمُؤْمِنِينَ

They said: O Hud! you have not brought to us any clear argument and we are not going to desert our gods for your word, and we are not believers in you:
2:8 وَمِنَ النَّاسِ مَنْ يَّقُولُ آمَنَّا بِاللّهِ وَبِالْيَوْمِ الآخِرِ وَمَا هُم بِمُؤْمِنِينَ

And there are some people who say: We believe in Allah and the last day; and they are not at all believers.
10:78 قَالُواْ أَجِئْتَنَا لِتَلْفِتَنَا عَمَّا وَجَدْنَا عَلَيْهِ آبَاءَنَا وَتَكُونَ لَكُمَا الْكِبْرِيَاءُ فِي الْأَرْضِ وَمَا نَحْنُ لَكُمَا بِمُؤْمِنِينَ

They said: Have you come to us to turn us away from what we found our fathers upon, and (that) greatness in the land should be for you two? And we are not going to believe in you.
7:132 وَقَالُواْ مَهْمَا تَأْتِنَا بِهِ مِن آيَةٍ لِّتَسْحَرَنَا بِهَا فَمَا نَحْنُ لَكَ بِمُؤْمِنِينَ

And they said: Whatever sign you may bring to us to charm us with it-- we will not believe in you.
23:38 إِنْ هُوَ إِلَّا رَجُلٌ افْتَرَى عَلَى اللَّهِ كَذِبًا وَمَا نَحْنُ لَهُ بِمُؤْمِنِينَ

He is naught but a man who has forged a lie against Allah, and we are not going to believe in him.
12:103 وَمَا أَكْثَرُ النَّاسِ وَلَوْ حَرَصْتَ بِمُؤْمِنِينَ

And most men will not believe though you desire it eagerly.

iQuran

بمؤمنين