I often heard people keep saying that they both are very similar, but tbh I actually don't think they're THAT similar. Maybe physical look for a bit.

I don't think they have similar personalities at all. I kind of get why people say they look similar, as they seem to have a similar base design.

They do have a few things in common, a slight stubbornness, refusal to conform and generally mature and dignified.

I wish there was a more "in between" answer

I had read this on IMDb upon the Princess and the Frog's release, mainly because they have the same supervising animator, Mark Henn.

Agree with wanting an in between answer. Mulan and Belle aren't dissimilar, but they aren't similar either.

the head-shape is similar and the eye shape are somewhat close, but they have different noses, different lips, different hair, different body shapes and they move very differently. And personality wise they have nothing in common.

i dont see what's common in them look-wise. Personality-wise i can say both stand up and stay-on what they believe in. Tiana is very aggressive in chasing her dreams, while Belle is more cautious and laid-back.

Personality-wise, Belle and Tiana only share these two traits: "self-righteousness in front of others, and snobbishness." They do have the same facial structure, same lip structure, and same eye structure, with the differences being Tiana's broader nose, darker hair, darker irises, and dimples.

Basically, to me, they look almost virtually the same.

Definetely!
They are almost opposites personality-wise. Belle is romantic and quite passive. Contrary to popular misconception, Belle isn't really serious, logical or realistic. Tiana is the least romantic DP IMO.
Physically they are similar, yes. Both are gorgeous women. The most beautiful of all DPs IMO.

^