Most Helpful Girl
Ask her if the jacket smelled bad to her. Sounds weird, but will probably prompt into her answering why she didn't take it.
"I couldn't do that. It's your jacket not mine" = not interested, was too forward
"You were cold yourself/Didn't want to make you" = you screwed up, she would've taken it
If she agrees the jacket smelled weird, she doesn't want to date you until you change body washes. Do not use bar soap.