často jí Kateřina hrusky, zatimco jeji manžel je nesnáší This is exactly what I put in. I know I missed a few things, but why was it ultimately not accepted? Word order?
missing často - often
and the word order. All our forms so far start with "Kateřina".
I did include často, but it's in the first position. Is that not allowed?
In general it is allowed: "Často jím hrušky." is perfectly fine. But your suggestion sounds unnatural. If you ask for a rule - sorry I don't know any rule that controls this.
How about "Kateřina jí hrušky často kdežto svůj manžel je nesnáší"?
No, in the second clause the subject is manžel so svůj directs his ownership to himself. That does not make sense.
"Nesnáší" would be translated as "hates"
It is not so simple. This translation is fine. To hate is more like "nenávidí" which is stronger.
What about "Kateřina jí hrušky často, zatímco její manžel jim nemůže obstát"?
No, "obstát" means "to endure". Obstát zkoušku, obstát u zkoušky - to stand the test.