Does your fiancé live in the US or drive across the border (daily?) for work?
The FAA and Transport Canada have a really good reciprocal arrangement. Even if you train in the US the effort to get matching Canadian licenses is minimal.
To fly for a US Carrier you will need to have the right to work in the US. "Fiancé" implies eventual marriage, hence my question above. If you are married to someone who lives/works in the US, then that gives you a leg up on being able to move.
I have a lot of friends in my glider club who fly for Delta. They are hardly flying. Two of Atlanta's runways have been turned into parking lots for jets. Until three months ago, if you had a degree, no criminal record, a commercial certificate, and 1,500 hours you were pretty much guaranteed a shot at a regional right seat. I think it will be at least a year before we see that again. Even decent starting pay and a signing bonus. Now...
You can train in Canada or the US. You can get certificates in either or both countries. I suspect there is more of an industry in the US to do "90-day wonder" or "zero to hero" type training programs where you walk out in 4-6 months with a commercial certificate and flight instructor rating at the end. Many of these programs hire their graduates to instruct the wave behind them. I believe there are "training for an ATP" visas that let you instruct for a year after graduation.
The time it takes to get through the paperwork, flight school, and accumulate 1,500 hours to be eligible would fit right in with the aviation industry needing a couple years to recover.
It's expensive training and time consuming, with no guarantees. But if you are sure it's what you want and you can get the right to work in the US then you can likely make it happen. Good luck!
Terry
Most schools are legit. Most want to get as many people trained as possible. My one suggestion is DO NOT PREPAY more than a couple thousand dollars at a time. If the place locks its doors it doesn't have your $100,000, and they have to keep you flying if they want you to keep paying them. (If you prepay, they already have your money, but owe you flying. They may spend faster than your fly, then the priority becomes the next paying customer!)