Expression of certainly and uncertainly

Expression of certaibly ( mengekspressikan keyakinan )

- I am sure                       = saya yakin

- I am certain                   = saya yakin

- I don't doubt                 = saya tidak ragu

- I amn't doubtful             = saya tidak ragu

Expression of uncertainly ( ketidakyakinan)

- I amn't sure                   = saya tidak yakin

- I amn't certain               = saya tidak yakin

- I doubt                         = saya ragu

- I am doubtful                = saya ragu

- I haven't decided whether to......................... or not. saya belum memutuskan untuk......................

Dialogue about expressing certainly and uncertainly

Tia : Oh my God, where is my wallet?
Rio : Are you okay?
Tia : I don't know. I think my wallet is lost.
Rio : Are you certain about it?
Tia : Definitely.
Rio : Don't worry. Let me help you to look for your wallet.
Tia : Oh.. Thank you so much, you're really my best friend.
Rio : you're welcome. By the way, where is the last place that you think your wallet already lost?
Tia : hmm, may be in the park.
Rio : Are you certain, your wallet is lost in the street to park?
Tia : I am uncertainty. I think it was lost in the grasses at park.
Rio : Are you sure?
Tia : I am pretty certain.
Tia : okay, let's search my wallet together.