Princess adores the Captain! He's sweet and noble and caring, and he's someone who can be baffled at future tech with her. She trusts him the most out of everying in the Enrichment Center, which is why she told him her backstory, and that really is a big deal for her. Rapunzel was raised to fear strangers and the unknown, and even though she's trying not to be that person with that fear anymore, it's still hard for her to mention hey guys immortality sun powers. Especially with Steve and his girlfriend who grew old, it's exactly the kind of situation she'd expect someone to come to her in desperation in, but Steve managed to be so kind and honourable that she went ahead and told him anyway (even if she did have to disconnect herself from it by telling it in the third person). She feels safe with him! She believes in Steve and his capabilities and thinks he's very strong, Rapunzel doesn't pay much attention to the little guy stuff because she's tiny herself, and thinks Pascal is so tough; even if he tires out from exercises sometimes Steve is still a cool hero who fights the system. She thinks it's very admirable that he's been through so much and lost his strength, and yet still never backs down.

Reverse?