then
If she wasn’t here then it couldn’t have been her.
in other words
‘He bought the wrong cake, and then forgot to meet her’
‘In other words: he’s an idiot.’
in that case
‘She’s a bit angry with you.’
‘In that case I had better go home early tonight.’
otherwise
She must not know, otherwise why would she still be here?
this implies that
He has begun hosting fundraisers. This implies he is thinking of running for mayor.
if so/not
Did you do it? If so, you only have yourself to blame.
in essence
The company has no money, and the creditors are asking for their cash. The company is, in essence, going under.