The Truth is from your Lord, so you shouldn’t be among the doubters.
This verse is repeated in verse 3: 60. The Truth mentioned in this verse is Adhikr. As Adhikr is Confirmed Truth mentioned in verses 56: 95 and 69: 51, only with It one can form a confirmed belief.
The Arabic Quran reading Fujjar by rejecting the Manifest Reading Adhikr are learning, teaching, and propagating books written by the pseudo-prophets and hypocrites. They are the Mujirims mentioned in 52 places such as in 7: 40; 18: 49 and 32: 22. They will wail on the Day of Judgment as told in verse 32: 12: “Oh our Lord! We have seen the scene of Hell and we heard its mourning, so you send us back to the worldly life to do righteous deeds, indeed, we have got confirmed belief”. It is told in verse 10: 94: “If you are having any doubt about whatever Lord has sent down into you, then you ask to those who are reading the Books before you, verily you have received the Truth from your Lord, so you shouldn’t be among the doubters''. The Fujjar are following conjectures and they are those who have a disease in their hearts as explained in verse 2: 78. So they will be in a never-ending doubt concerning every matter.
Verse 11: 17 ends as: “So you shouldn’t be doubtful about It, indeed It is the Truth from your Lord, but most of mankind is not believing”. See explanation 10: 57-58, 94, and 108.