Is there any verse in the Quran which cannot be grasped if God has guided him or her truly? In my understanding No.. Every verse of Quran is within the reach of every guided believer if his or her intention is guidance purely.. . So what in fact 3:7 is speaking about... So are there indeed verses we should classify that no one can understand them? No... If anyone says Yes! there are verses that should be classified that no one can understand except Allah then what are those verses and who will classify them and why? In that case also a loads of discrepancy in opinions will creep up.. But what I realized of late is, there is no such verses that are allegorical unless clearly stated with allegory in Quran while some other are very manifest .. I don't agree. In that case basic verses of siyam haj salah zaka etc are not at all clear for many who keep arguing for ages about it.. Coz guidance cannot vary.. I mean.. One fast skip food and drink 30 days in contrast to that one meditates etc cannot be guidance of God with the same verse... Coz one verse many interpretations is sheer crap..
If then, what exactly the verse 3:7 is meant by Allah? Yes.. Let's translate the verse first of all as meant by God. Coz complete Quran is fully detailed but only who are guided truly plus knowledgeable ones will understand them all, Allah wills .. People may raise voices in their ignorance but God knows who is guided aright with His verses.. There is no space for those who are guided aright for loopholes or ambiguity with certain verses so that get misguided literally .. Guided means guided to the truth and no other option.. So who will have ambiguity in Quran verses is in fact who has not yet reached to that point though thinks he so.. Intention plays a huge role here. . If the intention is Temptation (fitna) while looking at verses of Allah then they are not guided even how much they believe in God.. They are just curious with temptation /fitna and they alter rebelling with such verses..
Here is the translation of the verse 3:7
He (the God) is who has sent down to you the Book (kitab), of it verses self explanatory / self sufficient / comprehensible (Muhkamat), they are basic principles of the law (kitab), and the other (verses) dependent / equivocal (Mutashabihath). So as for those in whose hearts deviation follow what was reliant / equivocal of it, seeking the temptation (fitna) and desiring its result / fulfilment (thahweel). And not knows the result / fulfilment (tahweelaHu) of it except the God and those the well grounded in the knowledge. They say 'We believe in it, all from of our Lord'. No one receives admonition except men of comprehension.
Here.. 'Allah and those who are well founded in knowledge knows it' is a huge statement by God.. God only knows who those well grounded in knowledge who knows the verses of Mutashabihath. .. No argument about it and there are believers on this earth with such capacity... Just simply coz their immaculate intention which is guidance and not for boasting or temptation (fitna) ...
After all these Mutashabihath verses are just verses of Quran but need to study with thorough comparisons and much application of comprehension and that's why they are not muhkamat verses... Never these verses can be taken by reading only that verse/s itself but need loads of comparison and explorations and then judge... Well.. once judged God knows they have chosen the right path or not .. People may raise voice.against it but in vain coz they do only with temptation (fitna)..
Note well.. Results of digging deep with Mutashabihath verses are two :.....
1) failure . coz intention is seeking temptation in those verses...
2) Success.. coz intention is immaculate and well grounded in knowledge... Plus guided..
So in a nutshell... Guidance is never a guidance if gone against what Allah has revealed in the book though reading the same book. So ultimately it is between Allah and that believer.. Three options for the same verse cannot ever be guidance for three different people even though how much difference of opinion is welcomed / entertained in society... But not with Allah.. True guidance has no option save truth...