an astonishing achievement, you are amazing! How could you find so much time? How many hours do you invest daily?
When I am busy (finals week, for example), I may not do many lessons in a day, but I try to keep as many of my completed trees gold as possible and still make progress in the new ones. One five minute review can re-gild as many as four skills, so it doesn't take too long!
No, there is no verb in the Italian. While the meaning is the same; as a learning option we wouldn't add information.
What's the accent that i need to be careful of? Is it instead of a dot above the i?
Correct. You need the accent if you mean 'yes' (sì), because otherwise it can be confused with the 3rd person reflexive particle (si).
Why can it not be translated, "Yes, for sure." When I lived in Italy in the late 1970s, some Americans I was around used, "Per certo," which Italians tilted their head at and then indicated that just "certo" was correct.
In Italian vero is a synonym for certo, so I don't understand why it would be wrong.