Sponsorship through employment, or through family

[timmo]

Hi guys!
New here. Nice to meet everyone!
So I need to move to Canada.
My boss wants me to work in our Canada office and my girlfriend is Canadian.
She's been living here with me in the UK for a couple of years, but now that I have a great offer in Canada and she misses her family terribly, we decided to go.
I want to apply for a PR, but is it enough to present proof of employment? I hear it's hard to get in.
I wonder if we should get married... But I want to marry her when we're ready, not for immigration purposes...
What do you guys think?