Ez a ravasz kis szócska, BOND nem mindig fordítható szótárak alapján, amikor magyar megfelelői a kontextustól erősen függenek. Ebben a hagyatéki ügyben szerintem nem KÖTVÉNY a lényeg, hanem az, hogy a hagyatéki vagyonkezelő engedéllyel, biztosítással és biztosítékkal rendelkezik, így az örökösök jobban megbíznak benne. Angolul itt ezt úgy szokás jelölni, hogy "licensed, insured and bonded" - sok esetben még angol anyanyelvűek sem igen értik a különbséget, így az amerikai illető (gondolom, megbízott ügyvéd, esetleg magánnyomozó) megkísérli a magyar (feltételezett) örökösöknek elmagyarázni, hogy mit is jelent a "fiduciary" (ld. előző kérdésedet). Én úgy oldanám meg, hogy az insured lesz biztosított, a bonded pedig biztosítékkal rendelkező. Épp múlt héten volt nagyon hasonló szöveg a kezemben, ott ezzel a megoldással éltünk. Egyébként ugyanezek a terminusok használatosak közjegyzők vonatkozásában is. Az alábbi magyarázat talán segítségedre lesz:

"'Bonded'

Being bonded means that a bonding company has secured money that is available to the consumer in the event they file a claim against the company. The secured money is in the control of the state, a bond, and not under the control of the company. Let’s say that you hire a cleaning company and they end up stealing your Nintendo Wii. Well, you would file a claim against the company and, after an investigation, would be paid out by this bond.

This is slightly different but similar to what it means for an employee to be bonded. Being bonded in that case means that a bonding company has investigated your background and finds that you’re trustworthy and “good” enough to insure. In general, this is generally done when an employee has to handle large amounts of money or handle valuable property like jewelry or art. There is a very extensive and deep background check involved and what the employer gets is insurance that you won’t steal. If you do, then the bonding company pays out the amount of the theft. By being bonded, it shows that the employee is trustworthy enough for a bonding company to insure you up to a certain amount. Now, a company that is bonded means that a bonding company has funds.

Licensed

For certain professions, a license is necessary to show that you’re competent and permitted to conduct business in the city, municipality, or state in which the license was issued. For example, home improvement contractors will have to be licensed to perform certain types of work and that license number will be printed on every advertisement they print. You can take that license number and look up their performance history in most states through the Better Business Bureau.

Insured

This is probably the most commonly understood of the three (second to being licensed) and this refers to what happens if someone gets hurt on the job. Let’s say a company is fixing your roof and a roofer falls off and hurts him or herself. If the company isn’t insured, then the claim gets filed against your homeowner’s insurance (bad). If the company is insured, then the claim gets filed against the roofing company’s insurance.

In summary, it’s important that anyone you work with is licensed, bonded, and insured. There’s no reason why you should have to work with someone who isn’t all three, unless being licensed doesn’t apply. Once you know that they are, research and confirm that they are being truthful. I can say that I’m bonded, but unless I provide the documentation and you can verify it, I’m not actually bonded."

Ugyanez a helyzet a közjegyzők esetében is, azt közjegyzői biztosítéknak fordítanám. Lásd:
"Notary Public Bond
In order to provide some protection to the public, California law requires every notary public to file an official bond in the amount of $15,000. The notary public bond is not an insurance policy for the notary public. The bond is designed only to provide a limited source of funds for paying claims against the notary public. The notary public remains personally liable to the full extent of any damages sustained and may be required to reimburse the bonding company for sums paid by the company because of misconduct or negligence of the notary public.
(Government Code sections 8212 to 8214)

Itt van egyébként az a bizonyos 'Surety bond', amit a szótárakban 'biztosítéki kötvény' néven említenek, de abban nincs benne a Fiduciary, ami szerintem a kérdésedben lényeges elem.