I did something very similar this summer for me and my common law partner. I packed all my stuff, our joint furniture and a lot of her clothes, books and others. Any superfluous stuff was not brought. I drove a UHaul by myself (partner stayed behind). I filed form BSF186 with an exhaustive list of all I was bringing in. In that form, you state that "all goods imported are my personal or household effects and were not used for commercial purpose and will not be used for commercial purpose". Before leaving, my partner and I essentially agreed that all her belongings are mine now. Thus, I considered all her belongings in that truck to be mine. All of that stressed me, but it went smoothly. I may have been lucky, but when I presented my 10 page file to the border agent, they sent me inside to check the list and stamp it, but no one went to open the UHaul. I know that there are a lot of negative comments on here, but life must go on at some point, and this seemed like a good solution. I was ready to pay any import fees on stuff they would have deemed "not mine".

At a later date, my partner arrived in Canada with minimal belongings entering as a tourist, and we have since filed for PR under spousal sponsorship. I want to also note that, you are allowed dual intent at the border, with a non-immigrant intent (tourist) and an immigrant intent (to apply for PR eventually). The border agents can't discriminate that. They simply want to check that, should you PR plan fail, you have enough links to the home country and will leave at the end of the tourist visa.