Confiado

[ROBINDESBOIS]

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?

[Rusty]

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

[aleCcowaN]

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)

[poli]

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?

[Rusty]

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.

[aleCcowaN]

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 (--)