Walter Mazzarri's side have displayed inconsistent form in Serie A this season and still have work to do if they are to secure qualification for the UEFA Europa League.
A winless run of four games has come at a poor time for Inter, but Guarin, who is committed to the club until the end of the 2016-17 season, is remaining positive.
"I have agreed a deal for another three years. I hope to sign another contract once that one's up," he told reporters at a Nike event on Friday.
"I have not signed thinking that I will leave. I feel good here.
"It's been a difficult year, but we have to face up to those problems if we want to achieve our goals.
"We absolutely need to win the next game (against Sampdoria on Sunday).
"So far we haven't been lucky in any sense, this season. But we're looking forward to this weekend.
"We, the players, just have to think about the next game and then the next one after that. Sunday is fundamental for us. We simply have to win."
