Reporting statements: He {would/will} probably be back soon

Question

I'm wondering if there's any reason why will would be uncorrect in the following phrase:

She said that he will probably be back soon.

reporting the statement:

He's likely to be back soon.

The book I'm reading suggests to use would, should or ought to.

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Also for the following:

I refuse to accept that he is dishonest.

To report it I would have used either can't or couldn't (maybe she still can't believe it?)

She said that she can't/couldn't believe that he is dishonest.

I realize that the book may not write all the possible words, but am I wrong somehow?

Answer 1

She said that he will probably be back soon.

I think will probably is closer to the intended meaning of likely. Should or ought to are more middle of the road and imply some outside influence. (He should be back soon, but...)

I refuse to accept that he is dishonest.

refuse by definition has more to do with personal belief or motive (decline, reject), rather than can't or couldn't, which could negate for other reasons. I would keep ability in mind when using can.