AppleScript with a Pages Table to *Resize rows to fit cell contents*

Here is what I suggest, since there is no Pages AppleScript dictionary support to deselect "Resize rows to fit cell contents." After the paste, set the delay long enough to give you time to manually deselect that checkbox, then the rows will be set to their (real number) height.

Also, note how I use the code tool </> from this editors toolbar to paste code into the discussion and after the code, I press return and click the </> tool again.

use scripting additions

tell application "Pages"
	activate
	tell front document
		tell application "System Events" to keystroke "v" using {command down}
		delay 3
		-- manually click the Resize rows to fit cell contents checkbox to disable it
		set t to its last table
		tell t
			set its position to {81, 136}
			tell its rows to set height to 17.0
		end tell
	end tell
end tell

Does that work for you?

Or, more appropriately, make the row height changes and then deselect the current table:

use scripting additions

tell application "Pages"
	activate
	tell front document
		tell application "System Events" to keystroke "v" using {command down}
		delay 5
		-- manually click the Resize rows to fit cell contents checkbox to disable it
		set t to its last table
		tell t
			set its position to {81, 136}
			tell its rows to set height to 17.0
		end tell
	end tell
end tell
-- and now deselect the entire table
tell application "System Events"
	tell application process "Pages"
		set frontmost to true
		keystroke "a" using {shift down, command down}
	end tell
end tell

There is no Pages AppleScript dictionary entry named resizerows, nor as an undeclared variable of any type, you cannot tell the table to set anything to it. Further, the AppleScript dictionary does not give you access to toggling the [ ] Resize rows to fit cell contents selection checkbox as it is buried deep in the GUI design.

If there had been a practical way to toggle that checkbox, it would have been in my code response to your post. I chose not to spend hours, or forever, attempting to plumb the GUI object hierarchy for the code to perform that toggle event. Even if I had got lucky, there would be no assurance that the next point release of Pages would not break any GUI scripting as Apple has been known to reorganize their internal application code structure resulting in broken scripts.