Translation of Genesis 4:6
Yahweh said to Cain: Why (your anger) is burning? And why felt (the expression) of your face?
Translation of Genesis 4:7
If you would do well, (then) uprising. And if you do not do well, in the "entrance" sin lies. And on you is its desire. And you will rule over it.
"If you would do well" = "If mother would do well".
"Uprising" may mean that the smell of the sacrifice escalates to God.
We see that "sin" has its own desires.
It seems from this translation that Eve mis-raised Cain, and this was a reason of the murder.
There is the opinion that Cain and Abel conflicted because of a possession of a beautiful sister. This may explain "If mother would do well" to be the reason of the conflict. If the mother would do well there would be no conflict. However this is dubious because of having no article with the word "mother".
"you will rule over it" suggests that Cain was indeed saved and on the heaven he will rule over sin (sin on the Earth, probably).
Analyzing of information presented on this page is complete (even with spaces hypothesis). That is, all variants of translation were considered carefully. No warranty however, that nothing is missing.