The Walk the Line star has apparently told friends that she wants to wed boyfriend Jim Toth, a Hollywood agent.
Witherspoon and Toth began dating earlier this year.
A source told OK magazine: "Their relationship is very hot and messy, and she loves the excitement of it."
The insider added: "She isn't going to propose to him or anything like that - she's still a Southern girl at heart - but she has definitely dropped a few hints and he's absolutely head over heels for her."
It is said that the 34-year-old actress has been shopping for an engagement ring.
Witherspoon was previously married to Cruel Intentions co-star Ryan Phillipe. She split from former boyfriend Jake Gyllenhaal last year.
