I can afford to loose him.( ill , best )

please help me to choose the appropriate word from the bracket and insert it in the correct place.

also please explain the difference between the two words

I can afford to loose him.(ill, best)

The positioning of the adverb would be where there is an asterisk mark.

I can * afford to loose him.

Now, if the meaning needs to remain the same, the sentence would become:

I can best afford to loose him.

Also, if the meaning needs to be changed, quite opposite to what is given, the sentence would be

I can ill-afford to loose him.