A romantic Relationship is where both parts of the relationship share a mutal interest in each other that is greater than friendship in which they want to do couple things or have sexual attraction (hold hands, kiss, etc.)
A Platonic Relationship is where two people are intimate and close to each other but with no sexual attraction. This is often seen in people that are Siblings or Best Friends since they were little.
Where they are very close and do things that often if you were aquantiances with someone you wouldn't feel comfortable doing things with. Like be close each other despite personal bubble or share personal secrets.
For Example:
That one friend whom you're close with that may be the opposite gender or is your sexual orientation, but you consider yourself close to them, but would never consider being in a Romantic Relationship with.
In conclusion the answer is a friendly non-romantic relationship
