Jennifer Aniston has officially put herself back on the market.

While a source tells Us that the post-Vince Vaughn actress has been dreading having “to go through this whole dating thing again,” Aniston, 38, was spotted April 12 flirting and lauching with a blond mystery man during a dinner in a corner booth at the Sunset Tower Hotel’s Tower Bar in West Hollywood.

“He clearly held her interest,” says an onlooker, who characterizes the dinner as a “definite date.”

During her meal of salad with grilled chicken, “Jen was really into what he was saying and it looked like they were holding hands under the table,” says the source. “It was good seeing her enjoy herself with what looked like a new guy.”