Well, that is about 5.5 lbs of tent. It's a lot of weight however you look at it. There are a lot of pluses here, double doors/vestibules, good manufacturer, nice height, etc. It will get the job done. Your fiance will be comfortable or... as comfortable as she could be in a tent. And if you're splitting the weight its ok.
Here's the thing. We all want something and then wind up getting something else that we can afford and it rarely satisfies our need. I speak from experience. I've wasted a lot of money settling on gear I could afford only to figure out quickly that I really needed something else, and spending more getting that.
The Stormbreak will do what you need but it may nag on you when it comes to that last remark you made. "'m not a fan of the extra weight." It's hard to find a tent that will do solo trips AND be the perfect thing for her at a decent weight at $130. If price is the over-riding factor, you can't go wrong with the Stormbreak.
I'd add that you may want to check things out at used gear spots and see if you can get something a bit lighter that fits the bill. I just found a 2 lb 15 oz tent on ebay but it cost a little over $100 more than this.
As far as getting the fiance out goes. Make the 1st hike a short one to a beautiful spot with a full moon, good weather and bring a good meal, hot cocoa and plenty of bourbon. She'll love it.