A perfect way to make people think you have a new boyfriend is to show them you're in that beginning stage of the relationship where all you do is make out. Wearing a turtleneck, a scarf or anything that covers your neck will immediately make everyone think you're hiding a hickey and thus must have a new guy in your life who is totally into you.
After a few more "dates", you can move your fake relationship up to the next level by implying you spent the night at his house having sex. Simply show up in the same clothes as yesterday and watch the rumor mill start on its own. This step will not only convince people you have a boyfriend, but will also save you time and effort picking out a new outfit in the morning, and even money on laundry.
These jeans were invented to look like something you would borrow from your boyfriend. By showing up in ones, everyone will automatically assume they are not your jeans and that you and your new boyfriend are so close now, that you are comfortable enough to share each other's clothes. This is the kind of closeness you really want from your fake boyfriend.
Sure, every girl wears her boyfriend's clothes once in a while, for comfort. But only a girl in a really strong and healthy relationship will share her guy's most incredibly complicated and uncomfortable clothing items. A 3-piece suit says "my man and I love each other so much, we share both the good and the bad". Also, it looks dapper as hell.
Holy crap, girl! You're dating an astronaut? And he lets you borrow his space suit for work? Did someone say "wedding bells"?
Rumors about you are still floating around? Why not show up with cold hard proof! Go online and print a picture of a random dude to put on your shirt. Make sure it is in fact a random guy and not a famous model or worse - Jenny from accounting's boyfriend. That would be really awkward.
Who says I don't have a boyfriend, ha? Who? Then how come I'm literally wearing him?!