I can name a few successful sites that use escrow services and they don't call them anything other than escrow, and I'm guessing there's a good reason for that.

"Trust" is probably the last word I'd consider using.

"Escrow", in most people's minds, is a pretty straight-forward process that they already understand. They don't have to think too much about it.

When you throw in the word "trust" you are identifying that there is an issue there that your customers need to be concerned about.

If the site is strictly an escrow service, it might be different, but if you are offering a service where an escrow is a part of the process, I'd try to eliminate the "trust" issue alltogether.

Jim