Declan proposes to Katie next week, keen to prove his loyalty after the blonde falls out with his extended family members Megan and Robbie.
Teasing Declan's proposal, Winward told All About Soap: "She thinks he's joking, so she's like, 'Thanks for the offer - I'm just going to have a bath now'.
"But he insists that he's serious and gets out this massive diamond ring, and she says yes!"
Asked where things will go next, the actress replied: "I don't expect it will all go smoothly, but I think they will get married in the end. After all, Katie genuinely does love Declan. If she didn't, she'd have walked away a long time ago."
News of Katie and Declan's engagement may not be welcomed by Megan and Robbie following the recent tension.
Winward added: "Declan says that he'll throw them out once the festival is over, and Katie is pleased. When Megan and Robbie walk in after the proposal, Katie can't help giving the pair of them a smug look."
Emmerdale airs the proposal scenes on Friday, September 7 at 7pm on ITV1.