'Bachelorette' Trista Sutter Says 'Special Forces' Challenges Were Brutal

Trista Sutter says she's not cut out for life in the military ... because her first taste of Special Forces military training was brutal and intense.

The original 'Bachelorette' star joined us on "TMZ Live" Tuesday and we asked her about her experience on the upcoming season of FOX's "Special Forces: World's Toughest Test" ... and if there was ever a point when she considered throwing in the towel.

The reality show takes a group of celebrities and has them undergo grueling challenges from the playbook of the U.S. military's selection process ... and Trista says she was totally humbled.

Trista says a lot of her friends and family have been asking her if she had "fun" in her return to reality TV ... but she tells us why that's not the adjective she would use to describe it.

Instead, Trista says the only fun part was bonding with her fellow contestants.

When she was off filming, her husband Ryan Sutter made it sound like she was "missing" ... but Trista says her hubby was just trying to send a loving message to her and folks took it the wrong way.

Speaking of Ryan, Trista says he was her motivation here ... he's a former NFL player turned firefighter who dreamed of being in the military ... and she explains why she wanted to make him proud.

Catch the full interview today on "TMZ Live."