Ainsworth has taken the club to his heart since arriving from Rotherham, initially on loan, in 2013 and has decided to extend his stay in North Lanarkshire.
And the former Shrewsbury Town player said he was delighted to get his future sorted out.
He told Sky Sports News HQ: “You have to have clubs interested in you and at that time I didn’t know if there anyone was interested in me but I think I’ve got Motherwell etched on my heart now and they’ll be there for a very long time after football.
“I’m just so happy to be here and I’m grateful for the contract that I’ve got.”
The 28-year-old was part of the Motherwell side that beat Rangers in a Premiership play-off to maintain their top flight status at the end of last season.
Indeed, Ainsworth will be suspended for the first two games of the upcoming campaign after becoming embroiled in the post-match bust up involving former Gers defender Bilel Mohsni and several of his Motherwell team-mates.
However, despite enjoying winning those final games of the season, Ainsworth says the Well players have no intention of being caught in that situation again.
He said: “In my first season here when I came up on loan from Rotherham we finished second and that last day was crazy as well, beating Aberdeen 1-0 and we enjoyed that day.
“You are going to get your lows; last year was a low but the way we finished it was a high and all the boys will be thinking about it themselves, thinking we can’t finish here, we won’t allow it.
“So we know we’ve got to put in the work and push as high up the league as we can.”
Despite finishing in the play-off position last season, Ainsworth is adamant that Motherwell can return to the top six and challenge for a European spot again this season.
“I don’t see why not; we’ve been up there the last few years,” he said.
“I know last year was a bit of a dip but the manager will have his recruitment strategy going on – he can recruit well. He’s brought good players in so we’ll have to wait and see what happens there.
“The boys have got a determination to do a lot better for the club.”