The components of the word amoretti literally break down this way: amor, meaning love, and etti, meaning small or little. So the Amoretti sonnets signify the "little love" poems written by Edmund Spenser in the 1590s as a loving testament to his beloved Elizabeth Boyle, whom he eventually married.
The Amoretti sonnets are written in Petrachan form (see link below for more information on that) but also break with some of the traditions that Petrarch established. Instead of a typical longing for a love that can never be reciprocated, Spenser chooses to write of a love that is obtainable. Consider these lines from "Sonnet 22":
Her temple fair is built within my mind,
In which her glorious image placed is,
On which my thoughts do day and night attend
Like sacred priests that never think amiss.
There I to her as th'author of my bliss
Will build an altar to appease her ire:
And on the same my heart will sacrifice,
Burning in flames of pure and chaste desire.
Here Spenser explains the depth and nature of his love; it both burns like fire (which is interesting figuratively to juxtapose with religious images such as altar and sacred priests) and is pure. In various sonnets, we are presented with various descriptions of this love (including his beloved's pride and the fact that in the beginning sonnets she "makes [his] pain her sport"), showing the complex nature of love itself.