Would my manager ask me for proof?

First Off: WELCOME TO THE REAL WORLD :)

Now to answer your question: There's no need to lie. They will Most likely NOT give you weekends off! Burger King like most retail establishments experience heavy businesses during the weekend which means those are the times they need you the most. If you don't want to work weekends, I suggest you start looking for another job (try assistants or some kind of office job where they are closed during weekends or maybe a part-time on campus job)

Real world tip for you for future reference:

Newbies (person who just recently start a job) always gets the worse hours/work. Person with seniority (someone thats been with the company the longest) usually gets the best hours/work or hours/work they want and trickles down to manager's favorite and lastly YOU the newbie. You get everything that no one else wants. Its just the way it is until someone newer comes in ;)

Say this to your manager, exactly how it's written, (what you wrote) "I work every single weekend now & it's getting to the point where I'm getting kinda mad. I used to use my weekends to get away & relax, de-stress myself. I have college to worry about & my crazy life, I'm going nuts." and I'll add to that with "may I please have some weekends off or I think I might lose my mind."

As long as your manager is not a complete 8=D Then it will work, and you won't have to lie about having another job. If you lie about having another job on the weekends you can't take that back. What happens if because of that they give you every weekend off, but then you run into money problems and need the extra hours. Your boss won't give them to you because they're under the impression that you are getting them elsewhere.

But also keep in mind that you are a grown up now, so you have to act like it, and grown ups have to work weekends. If you just tell you're manager "I'm not working weekends anymore, I want to have fun and party" then your manager will likely say "f*ck her, she can work every weekend". But if you say, "I'd be willing to work some weekends but I need to have some off as I am also in school and need some time for homework." If you work with them then they will work with you. If you don't settle for anything but your way, then you will never get your way. This is the real world.

As an example. A girl at my work worked mon-fri from 4pm to midnight. I work sat-sun from noon to midnight. She was complaining that next semester her classes were mon, wed, thu during her regular shift. She was demanding from the manager that they give her the day or night shift because she's in classes and she has seniority. But there were already people working those shifts who had schedules set around those shifts. They're not just going to move everybody around because she needs to change her schedule. I offered to her that I would work mon, wed, thu and she could have my weekend shifts. She maintains her 40 hours, I maintain my 24 and she gets the schedule she needs for school. Everybody wins. She immediately denied the offer stating that she doesn't work weekends and demanded that one of the other people give up their shift times. She is no longer employed with us. They fired her a$$ because she was unwilling to bend.

You can just tell him/her that you have study/college and you cannot work on weekends. You need to work to earn your livelihood, but you also need to give time to your study. I hope he will understand the matter.

Even if you had proof, they don't have to say ok. They can just tell you to choose ot be fired. So you'd be telling a lie for no purpose.

Just say you aren't available on weekends you don't need to lie about it.