'Bachelorette' Contestant Peter Kraus Tells Rachel Lindsay He Might Not Propose

Rachel Lindsay got treated to a harsh truth on "The Bachelorette" from one of her favorite suitors ... with him telling her he won't propose if he isn't ready.

Fan fave contestant Peter Kraus got brutally honest with Rachel on Monday night's episode -- first telling her a super sad story about his last girlfriend, and then saying if he felt any doubt about proposing come game time ... he would let her know.

It's a bold move on Peter's part -- she could've cut him right then and there. Lucky for him, Rachel seemed to appreciate the truth more than the possibility of being left hanging by the end of the show ... and she gave him a rose.

Rachel will be meeting Peter's fam next week ... and those of at least a couple other contestants.