Is it grammatically correct to say: Your understanding is correct to re-assure a concept?
Here are thefreedictionary's (relatively) distinct senses for the noun understanding...
1: The quality or condition of one who understands; comprehension.
2: The faculty by which one understands; intelligence.
3: Individual or specified judgment or outlook; opinion.
4: A compact implicit between two or more people, or the matter implicit in such a compact.
5: A reconciliation of differences; a state of agreement: They finally reached an understanding.
6: A disposition to appreciate or share the feelings and thoughts of others; sympathy.
...where the highlighted entry applies in OP's case (your understanding = what you think).
This shift in meaning from the generic ability to understand in #1 to the specific thing understood in #3 is quite common in English, and can be seen with many other words...
My reading of the situation is that we are under attack by extraterrestrials.
Your thinking is completely off-the-planet.
My sense is that we are living in different worlds.
...where highlighted words are implicitly "particularised" to refer to the specific concepts following.