Just as slow as the original, but I'd argue it's a better film overall.
There isn't much between the two films, I admit. However, I found 'The Princess Diaries 2: Royal Engagement' more enjoyable than 'The Princess Diaries'. The plot is probably just as interesting, but there's less cringe in this one and the villains are a big improvement.
Anne Hathaway (Mia) is very good once more, while Julie Andrews (Clarisse) does solid things again. John Rhys-Davies (Mabrey) and Chris Pine (Nicholas) are top additions, great casting on the latter by the way given it's Pine's feature film debut.
I also said in my review of the 2001 film that I don't like fictional places in live-action, non-fantasy productions. That's still the case here, but I didn't actually mind it all that much to be honest. "Genovia" is way more believable here, thanks to us actually getting to see it for real - as opposed to it just being referenced.
As noted, there are still a few cringey moments and it does run too long. There are some sweets parts, though. It's also kinda weird that, technically, Mia and Nicholas are related; a number of generations back sure, but still...
A sequel that (minorly) improves on its predecessor, that's always a positive in my book.