'Bachelor' finale sneak peek: Nick Viall tearfully prepares for a proposal

— -- It's the season finale of "The Bachelor" and you should expect tears.

In an exclusive preview, Nick Viall tearfully reveals that he's decided who will receive the coveted final rose ... and of course its accompanying engagement ring.

"I've been falling in love with her for a very long time," he says in the preview, before cutting himself off as his emotions get the best of him. "I feel like sometimes I've been fighting it and I'm not fighting it any longer."

Tonight's finale, which airs on ABC, comes after Viall said goodbye to Rachel on last week's episode.

In the preview, Viall admits he's nervous about what the outcome of his proposal could be.

"I'm going to ask her to marry me and my only fear now is what if she says no," he said, noting that "it didn't work out" for him in past seasons of "The Bachelor" franchise.

"I'm just trying not to be afraid," Viall added. "If I leave here alone I'll be devastated. I'll be heartbroken."

Find out who Viall is talking about -- either Raven or Vanessa -- when "The Bachelor" returns tonight at 8 p.m. ET/PT.