Confiado

Confiado
 

How can we say ser confiado in the sense that you trust people so much that you think nobody is going to rob you.trusting maybe?

(too) naive
(too) trusting
(too) gullible

Laura - "Did you get him to sign the papers?"
Tyler - "Oh, yeah. He's a very trusting man. He thinks everyone's honest."

from The Beverly Hillbillies (1993)

You should note that the word trusting is positive, and being trusting is a virtue.
On the other hand, gullible is not and it doesn't require too in front of it to sound negative.

I think confiado usually has a positive meaning. Am I wrong?

It has both a positive (confident) and a negative (naive) meaning. The OP is interested in the negative meaning. One who is too trusting, gullible or naive can be robbed blind.

confiado = seguro de sí mismo (+) self-assured ---> anglicismo muy usado (y mal aprendido) en doblajes -no existe en castellano

confiado = que espera lo mejor -with an expectation of positive outcomes-

confiado = no desconfiado (+); que deposita su confianza en otros con facilidad / que cree que todo va a salir bien sin tener certeza de ello (-)

muy confiado = crédulo, ingenuo (-); imprevisor (-)
demasiado confiado
se pasó/a de confiado = exageradamente crédulo (--); extremadamente imprevisor (--)