The "Shake it Off" hitmaker insists she can handle those who have wronged her personally, but does not feel the same towards those who mistreat the pop star.
"I knew from when I met her (Selena), I would always have her back," Swift tells The Wall Street Journal for a profile focusing on Gomez. "In my life, I have the ability to forgive people who have hurt me. But I don't know if I can forgive someone who hurts her."
Gomez also discussed their bond with the publication, noting they are even closer than they appear to be publicly.
"There's so much of my friendship with Taylor that people don't know about because we don't necessarily feel the need to post about everything we do," Gomez shares. "She has showed up for me in ways that I would have never expected. Flown in because I was hurt and was going through something. Stuff that was going on with my family."
The 27-year-old shares that Swift has been a devoted supporter of hers for many years.
"It's been proven year after year and in every moment of my life that she is one of my best friends in the world," Gomez continues. "We don't agree on everything, but we respect each other with everything."
Gomez also sought Swift's approval when it came to her new album "Rare".
"This is the first time I've heard her truly channel the details of her emotional experience," Swift says of the release. "I just thought, 'Wow, she's finally allowing herself to let other people know things aren't always OK'."
She adds, "You can be vulnerable and lonely and independent and strong and brave and scared all at once."