In the last joint public sighting of Lauren Conrad and Heidi Montag -- on the latter's wedding day to Spencer Pratt -- the former BFFs seemed to move past their mountain of problems and break bread. But nearly six years after that fateful "Hills" occasion, Heids is still struggling to let go of her deep anger toward her erstwhile roomie. Get ready for the birthday boat excursion 2.0...sans LC, of course.

Heidi -- who is trying to work through her issues with her crystal-loving hubby on "Marriage Boot Camp" -- admitted in the clip below during a "forgive and forget" activity that she needed to let go of her rocky history with LC in order to free herself from the drama. The kicker: The Colorado native had to face a woman, posing as the fashionista and bestselling author, and leave nothing to the imagination. And boy, did Heidi go there...

"Lauren, I forgive you for being so insecure in your life -- and so frustrated for everything that you went through -- that you felt like you had to blame it on me," 1/2 of Speidi blurted through tears. "I forgive you for trying to ruin my life."

But it didn't stop there. Heidi stated that she will no longer have resentment toward her fellow SoCal lady.

"I do love you, despite everything you have done to me," an emotional H claimed. "I do. I wish you the best."

Unsurprisingly, Mrs. Tell has yet to weigh in on Heidi's confession -- but in a perfectly ironic twist, she did once utter those two words at the root of Heidi's recent exercise. Relieve their priceless old-school interaction from their Hillside Villa days below, and share your thoughts about H's admission below.