An evocative work that uses undulating arpeggios to represent the title's fluctuating sentiment. Its harmonic language is rooted in 19th-century Romanticism with a touch of South American lyricism.
Achieving a smooth, wave-like motion in the left-hand arpeggios is necessary to keep the melody from feeling stagnant.
Comparable difficulty and character — good candidates for what to learn next.
Amôr fluctuante is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 4.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Amôr fluctuante lasts about 3 minutes.
Amôr fluctuante is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include 18 de Julho by Benedicto Bueno de Camargo, Brise lointaine by E. Clérambault, As in a Rose Jar by Charles Wakefield Cadman — see the full similar-pieces list on this page.