To-infinitive

lucas21could you tell me whether the following sentence is okay?

It is unnecessarily ambiguous. Recast it.

Could you tell me why it sounds ambiguous to you? To me, it is interpreted only as he hired a lawyer so that he would divorce his wife.

I'd like to know the other ways that it could be understood. (I can't edit the above post any more, so I add it here.)

It sounds as if it might mean that the client wanted the lawyer to divorce his own wife.

Ah, I see. Then, how about "I hired a lawyer to divorce my wife?" Is it right and natural?

lucas21cI hired a lawyer to divorce my wife?"

That's better. But a natural escape from the problem is 'I hired a lawyer to handle my divorce.'

Is the pronoun his after lawyer that causes the ambiguity?

The ambiguity that I was pointing out was because of "his." But really, the problem is that normally you "hire someone to do something." Look at these sentences and you'll see why yours does not work:

He hired a painter to paint his house. He pays the painter, and the painter paints the house.
He hired a gardener to cut his grass. He pays the gardener, and the gardener cuts the g

Then, is "He hired a lawyer to handle his divorce" also possible?
(I think it is because we know no one can handle someone's divorce without attorney license)

lucas21cThen, is "He hired a lawyer to handle his divorce" also possible?

Well, that was one of my suggestions, so yes, I do think it's possible.