how do i say that i got the best answer?

Do you mean you want to choose a best answer? You dont do that by emailing.

Here is how to choose best answer- 4 hours after posting the question. ( If it doesnt have any answers, then go back later.)

Then go back to your question by mousing over the My Activity Tab, then click My Q&A. Click Questions. Choose the question you want. Read each answer carefully. You can only choose one best answer. Click Choose As Best answer under the answer you want to choose. Then choose the rating 1-5 stars with 5 being the best. Then write how you think of the question. Click Submit. Now you have gotten 3 points for chooseing best answer.