She is wiser than intelligent.
She is more wise than intelligent.
Although the second sounds good to me, I want to know whether there is any rule for this?
I agree, the second version sounds better, and I would not see anything wrong with it.
The first sounds odd because a person is being compared directly to a adjective,
She is wiser than intelligent
whereas we usually compare two or more things, or people.
She is wiser than most people (comparing people)
The owl is said to be wiser than the fox (comparing animals)
It is wiser to check shipping costs than presume you are saving money. (comparing costs)
Online, there are several question about He is more wise(r) than brave but I’m not sure about the grammatical explanations offered.
- When two qualities of the same person or thing are compared, the Comparative in-er is not used. ‘More’ is used for this purpose.
Incorrect- He is wiser than brave.
Correct- He is more wise than brave
(Source: SSC Exam Preparation)
Elsewhere… (Campusgate )
Which looks reasonable unless you missed their earlier example, which is clearly wrong!
Hunting in Google Books, the following examples caught my attention
It is a most agreeable and fascinating cullibility, whereof it is more wise than foolish to become the willing and unresisting dupe.
No nation is more wise than the English in managing their own market.
This territory is apportioned, in separate Governments, to the different sons of the Ameer, a policy which is more wise than popular.
it is a veil over his wisdom; remove his eloquence, reduce his language, withdraw his images, and you will find that he is more wise than eloquent.
I don’t know if the examination prep website or my explanation above helps explain why writing “more wise” is preferable or acceptable but safe to say it is grammatical, despite wise being monosyllabic.