The Red Devils booked their place in the May 21 final with a 2-1 win over Everton on Saturday.
And Roo believes lifting the cup could prove to be the boost the club needs to lift them after three trophyless seasons.
The skipper: “I’ve played in two FA Cup finals and both have ended up in defeat.
“It’s a cup I haven’t been lucky enough to win yet, so it’s a good chance for us.
“Whoever we play in the final, I’m sure it’ll be a tough game for us. I think the fans deserve it - they’ve got to come to Wembley for a cup final, and we have to give them a good performance.
“I think it’s a great opportunity for us. There are a lot of young and new players in the dressing room for us, so it could be a big day for us in the final and the start of something special for us, I hope.”
United will face Crystal Palace in the final after their 2-1 win over Watford last night.