Here's a really clean copy of this Canadian comic - Diary Secrets #4:

I was looking at the Superior Publishing title listings on Grand Comic Database, and they have listings for both "Diary Secrets" and "Teen-age Diary Secrets".  The early St John published books are confusing enough to track, but compound that with foreign printings...  well, CGC seems to label it by the TADS USA information with a small font notation of the actual title:

But I don't want to belittle CGC too much for this ridiculous label, because the CGC case actually saved this book from damage after being run-over by a truck.  Thank you for that, CGC.

This book is indeed "Diary Secrets #4", published November 1949 by Superior Publishers Limited (Canada).

Another one that has yet to be entered into the GCD (yes yes...  I'll get to it someday).  I believe this copy came to me by way of another Board Member's consignment to a large auction house.  Hey Boardie, do you recognize your old book?

Similar to my other Canadian St John reprints, this book mirrors it's USA counterpart with the exception of the advertisements.  We even get another Fun Balloons ad with the first Matt Baker story ("I Gave Boys The Green Light"):

Might as well share some more of those cool ads....

Next Matt Baker story art (early Baker work, and perhaps why GCD is listing these as his inker's work - Mr. Ray Osrin) is "I Cheated... for the Thrill of it":

And finally the last of the Baker stories, "I Liked Older Men"

There are some strange printing "defects" on this copy.  Extra staples showing at the centerfold and a miscut back cover edge...

If I'm going to guess, I'd say the first "original" cover was mutilated during production and a second/spare "new" replacement wrap was added.  I have seen this on St John comics too.  Only one set of staples go through the outer wrap, but not both sets.

This Canadian comic is a more manageable size than it's USA version:

...and since I have a ragged copy of the USA book close at hand - I took a photo of the two together!

It's apparent how the paper stock affects the sharpness of the printed photo cover.  The USA version has that nice blending of ink that sits on the surface of the paper due to there being less "tooth" to the paper and makes it appear glossy.  The USA copy is also near magazine size.

I concur with CGC's assessment of the grade at 5.0.