I want you to understand what I said.
What does this sentence mean?
1. It's what I want that you understand what I said. (Referring to the present)
2. It's what I want that you will understand what I said. (Referring to the future)
3. Either 1 or 2 according to context.
I think the sentence means 1 or 2 according to context.
If the sentence is written to describe his present understanding about what I said, I think option 1 is correct.
fire1 1. It's what I want that you understand what I said. 2.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
fire11. It's what I want that you understand what I said.
2. It's what I want that you will understand what I said.
These are both ungrammatical, so it's impossible to answer your question.
But wanting implies a future. If something already exists in the present, there is no reason to want it. Maybe that's all you wanted to know.
CJ