I am not sure if I will manage to do this task
I think that this colour suits me.
In my opinion, this team will win the match.
I don't think that she will decide to marry him.
I am sure that there will be no problem about your coming.
As far as I am concerned, butterflies are beauiful
I consident that... ( nie znam słówka consident) jeśli consider powinno być to np I consider doing that.