has he done any thing like this before?
How did this come to the attention of the police please?
Did she see it?
Well, that is a problem then.
Even if you don't give evidence they will rely on her evidence.
What he will get depends on the nature of the allegation but people don't usually go to prison unless the offence is very serious or the offender has a horrendous history.
Can I clarify anything for you?
Well, it depends on the nature of the allegation.
'A black eye' is too vague. It could be a common assault of an ABH.
If you are clearer then I might be able to offer more.