يَسْتَعِيْذُ بِاللهِ
One should seek refuge in Allah
One should renounce that which is causing such doubt.
يَقُوْلُ: آمَنْتُ بِاللهِ وَرُسُلِهِ
One should say: ‘I have believed in Allah and His Messenger.’
يَقْرَأُ قَوْلَهُ تَعَالَى – هُوَ الأَوَّلُ وَالآخِرُ وَالظَّاهِرُ وَالبَاطِنُ وَهُوَ بِكُلِّ شَيءٍ عَلِيْمٌ
One should also recite the following verse:
‘He is The First and The Last, Ath-thahir and Al-Batin and He knows well all things.’
Source: Hisnul Muslim