Oof… I wrote quite a lengthy reply but the Studen Forum didn’t accept it. I think because I copy and pasted a link.
There are several stages to the realisation of emptiness. There are two main presentations at the Sutra-level.
1. 5 Stages Bodhisattva Path, that incidentally map to the mantra in the Heart Sutra:
1. Gate 2. Gate 3. Pāragate 4. Pārasaṃgate 5. Bodhi Svāhā
2. Ten Bodhisattva Bhumi.
In brief, long before we gain a direct realisation, there is a process of going from doubt tending towards non-emptiness, equal doubt, doubt tending towards emptiness, correct assumption, and valid inference. Each of these stages represents a gradual process of cleaning up, deepening, and intensifying our conceptual understanding of emptiness. Correct assumption is 100% correct, but still subject to doubt due to lacking intensity. Valid inference is 100% but no longer subject to doubt due to intensifying the correct conceptual understanding in a state of meditation. This is a debate point, but some argue you can gain a valid inference at the 4th level of shamatha, and that once attained you cannot have an unfortunate rebrith. You’re on your way out.
Also, properly contemplating emptiness counteracts everything dysfunctional in your mind and reinforces everything positive in your mind. So, even just the correct conceptual understanding of emptiness is quite powerful. It’s also not quite so far off as the direct perception. Though, the direct perception arises due to wearing out the need for the correct conceptual image. The direct perception isn’t somehow ‘more correct’ about emptiness, but rather dramatically increases spontaneity. So, rather than needing to go through the lengthy process (even just a few moments is lengthy… my mentor used to say ‘This small time gap is wide enough to drive the full mack truck of samsara through’) of generating a correct conceptual image, you look directly and see the emptiness. Also, there is a difference in intensity between seeing emptiness directly and holding a correct conceptual image of emptiness in meditation. That said, I’m at the limit of my knowledge on this aspect. There are many more here who have some experience to back up their words, unlike myself.