Here is the item again:
Julina would never again agree to go out to dinner with
James,
he expected her to buy her own meal, tip the waitress, and chip in
for gas.
Julina would never again agree to go out to dinner with James is a main clause. He expected her ... begins a second main clause. To connect two main clauses with just a comma is to commit a major sentence error, a comma splice.
If you were to use the comma with for, a coordinating conjunction, you would fix the problem.