Arggh, stupid English.
Lol XD. French has a funny word that sounds profane in English.
Would "Suas facas" mean Your knives as well?
It could or it could mean "his knives", "her knives", "its knives" (a robot?) or
Yes but Suas is formal while Tuas is informal.
Why is knife spelled with v?
The only definitions I found for knive was:
to cut, pierce or kill with a knife,
A brawl ensued among the friends and he was knived to death.
If a word ends in -f or -fe, you take its plural by removing f/fe and adding -ves: leaf - leaves, loaf - loaves, shelf - shelves, wolf - wolves, knife - knives
So alternatively, would it be você facas or vocês facas? And why?
"Você/s" = you, not "your".
Maybe if you were for some reason addressing the knives...?