Did the Muslims of Granada expect their Christian conquerors to keep their promised terms?

When historians tackle this kind of issue, they normally do so without taking into account the most important thing of all: the human factor.

Both Christians and Muslims, conditioned for centuries to loathe one another, could not renounce "the old ways" just because some kooky treaty was suddenly signed and ratified. Individual cases depended heavily on how much money this or that family had; whether they could be attacked with impunity; whether the living conditions of their neighbors were dire enough to justify such attacks in their own eyes; and so forth.

The role of the Spanish Inquisition in this, and other matters, is highly exaggerated and cannot withstand close scrutiny. Depending on what sources you choose to get information from, the actual number of heretics burned at the stake during the rule of Torquemada, a man of partial Jewish heritage who hated Jews indiscriminately, is laughably small compared to other movements in history that involved killing people.

OF COURSE Christians, especially those who were financially challenged, attacked Muslims. OF COURSE Muslims, especially those who were financially challenged, attacked Christians. That's because humans in general don't deal in morality, fairness, judiciousness, and so forth: when your lifestyle isn't everything you hoped for when you were younger; and when you're guaranteed (sort of) impunity, all you need to attack your more successful neighbor is an excuse.

The Spanish Muslims had "some" reason to expect that the Spanish would observe their rights.

The "Reconquista" had been going on for several centuries, and the Spanish had (earlier) more or less observed treaty terms in the newly reconquered territories. This "observance" had become less as time went by.

Three things made the fifteenth century version "different."

1. The Reconquista was completed, not "in progress" by 1492, meaning that people could think, "let's settle up the final scores."

2. Protestantism was becoming a threat, and the Spanish inquisition was influenced by the anti-Protestant "inquisitions" going on elswhere, and

3. There was the incalculable contribution of this one man, Tomas de Torquemada, the personal confessor of Queen Isabella. He himself came from a family of converted Jews, and sometimes "converts" are harder "on their own kind" than "native sons."

From additional research I have clarified this answer to better reflect the documentation from Spanish Historians who have provided much more detailed commentary and record of the events of the Grenadian War.

Your initial question asks if the Grenadian people believed that the Spanish would be faithful to the terms of the surrender. The Spanish Wikipedia article references Luis María de Lojendio in his historical chronicle Gonzalo de Córdoba (p. 90), and has this to say about the negotiations:

Las últimas negociaciones secretas incluyeron el respeto a la religión islámica de los que decidieran quedarse, la posibilidad de emigrar, una exención fiscal por tres años y un perdón general por los delitos cometidos durante la guerra.

Which I have roughly translated with the assistance of Google Translate to:

The last secret negotiations included respect for the Islamic religion of those choosing to stay, the possibility of emigrating, a tax exemption for three years and a general pardon for the crimes committed during the war.

It is clear that the terms of the surrender were secret and known only to the signing parties. Which had later consequence as the Grenadians found out..

Antoni Simón Tarrés a modern Spanish Historian published La Monarquía de los Reyes Católicos (A Chronicle on The monarchy of the Catholic Kings) (page 56). His work is referenced later in the Wikipedia article mentioned above, in which we can glimpse the reaction the Grenadian people had to the terms their leader had handed them over unto.

El 25 de noviembre de 1491 fueron firmadas las Capitulaciones de Granada, que concedieron además un plazo de dos meses para la rendición. No hubo necesidad de agotarlo, porque los rumores difundidos entre el pueblo granadino de lo pactado causaron tumultos, sofocados tanto por los cristianos como por los fieles a Boabdil, que acabó por entregar Granada el 2 de enero de 1492

Which I have roughly translated to with the assistance of Google Translate:

On November 25, 1491 the Treaty of Granada was signed, which also granted a period of two months (for the Grenadians) to surrender. Before this period ended, rumors that spread among the Grenadian people of the agreement caused riots, stifled by both Christians and Boabdil loyalists, which eventually gave Granada over on the January 2, 1492

Rioting in this case, is a direct result of the Treaties signing. So it is evident that a group of the Muslim Residents of Grenada had no trust in the Spanish to Maintain the treaty.