The actress’ father died from a heart attack in 2013 at age 62

Rebel Wilson with family members in 1995.

Rebel Wilson and her father Warwick had a complicated relationship.

In her upcoming book Rebel Rising: A Memoir, which is excerpted in this week’s issue of PEOPLE, the Pitch Perfect star, 44, recalls writing a heartfelt letter to her dad and putting it in his pocket after he died in 2013 at age 62 from a heart attack.

“To dear Dad,” Wilson writes, “I’ve said a lot that you were never really part of my acting career, but on reflection, you were and are. There’s a cheekiness, a dodginess and entrepreneurial-ness, a darkness, a creative-ness, a bravado-ness that comes from you and your side of the family.”

“I thank you greatly for that,” the star continues. “I’m sure you didn’t mean to bring so much pain to Mum and us kids. You didn’t mean to lose your temper and do spiteful and hateful things.”

“I want you to know that I forgive you. I will strive to find love, I will no longer be afraid of it,” Wilson adds, signing off: “Your daughter, Rebel xoxo.”

Rebel Wilson, cover of ‘Rebel Rising.’.

KARWAI TANG/WIREIMAGE; SIMON & SCHUSTER

Rebel Wilson Reveals Daughter Royce’s First — and Now Favorite – Word: ‘It Melts My Heart’ (Exclusive)

Speaking with PEOPLE ahead of her memoir, out April 2 from Simon & Schuster, Wilson opens up about how it felt to detail her rocky relationship with Warwick.

“At one part, it is easier because he’s passed away,” she explains. “And I wonder whether I would’ve had the courage to do it if he was still here… [so] it’s a little bit easier, I guess, in that respect that he’s not.”

“But that is also something that I’ve never spoken about before, and it is cathartic, I think, to write about it,” the Bridesmaids star continues.

Speaking about her father, Wilson notes that their relationship “wasn’t so black and white.”

“There were all these other things — the sadness that I felt when he did pass away so suddenly, and how tragic that was, and how I have regrets,” she says. “It surprised me by writing [the memoir], sometimes, the empathy I felt towards him and thinking about his life and his struggles.”

Rebel Wilson as a child in 1987.Rebel Wilson Says She ‘Got More Attention for Weight Loss Than Any Movie’ She’d Ever Done: ‘People Are Intrigued’ (Exclusive)

Wilson also spoke to PEOPLE about the his anger issues when she was a young girl and how he occasionally hit her.

“I think it probably led to not having good self-worth, and also thinking you had to be good all the time, being a good girl and not being naughty,” she says. “I was not naughty in any way because I think I was fearful.”

Wilson is now a mother herself to a 16-month-old daughter Royce. She adds: “At school, I would be very good and get very good grades, and I would never talk back or be disrespectful. I never smoked or drank or did anything naughty because I would be scared. … So I always had to be a very sensible and responsible child.”