"this marvelous" is correct and usable in written English.
You can use this to describe something that is wonderful or extraordinary. For example, "This marvelous sunrise made my morning."
This marvelous show starts settling the dust.
This marvelous artist, rightly, has the final bow.
The timing of this marvelous book couldn't be better.
With the third innovation in science and technology worldwide, China has also experienced this marvelous progress.
Over the course of this marvelous show, that equation is under constant adjustment.
Read this marvelous book and your eye for color will snap back into brilliant focus.
I don't want to spoil this marvelous, redemptive revival's resolution of that discrepancy.
This marvelous company makes the rare truces as memorable as the brutal battles.
And what a riveting tale Lawrence Wright fashions in this marvelous book.
This marvelous collection must be one of the greatest tributes to Anonymous ever constructed.
It's O.K. We have this marvelous game we play when he's feeling good.
