Question

write 5 example sentences of expressing Certainly and expressing obligation?

Answer 1

Are you sure? Yes, I am certain. Are you sure about it?  I’m a hundred percent certain … Do you think it is true? I have no doubt about it. How sure are you?  I don’t think there can be any doubt about …

Answer 2

- - - cetainity
Yes, I am certain.
 I’m a hundred percent certain …
 I’m absolutely sure.
 I have no doubt about it.
 I’m sure about it.
 I don’t think there can be any doubt about ….
 Of course.
 I’m positive.
 I’m quite sure about it.
 I’m no doubt about it.
 I’m absolutely certain that…
- - - obligation
must
need to
It is necessary
 to have
 to have got to
I am obligated/obliged to