The phrase "a gentle note" is correct and usable in written English.
It can be used when referring to a soft or kind message, often in a context of communication or expression of feelings.
Example: "She left a gentle note on his desk, wishing him a speedy recovery."
Alternatives: "a soft message" or "a kind reminder."
On a gentler note I spent one morning this week sitting alongside the judges of the MCC/Cricket Society book award in search of a winner.
Things begin on a gentler note: after Eric Jackson Bradley bows to his shadow, cast against the back wall, Toni Melaas takes possession of the stage for a surprisingly lovely dance with a green helium balloon.
On a gentler note, the first big geodesic dome to make an impression on the public, built for the1964 New York World's Fair, is today the much-loved aviary of Queens Zoo.
He hit a high, gentle note by reminding his team, as well as observers, that about 250 other college teams would love to be 13-5 and ranked in the top 25.
And then, very slowly, a classical melody is played on a piano, one gentle note at a time.
Though it is relatively gentle, note that over-applying can have a drying effect; to create a more skin-friendly paste, mix baking soda with honey, apply it as a mask, and let it sit for at least ten minutes.
It will introduce a gentle citrus note.
Herbert Howells's Long, Long Ago was a heartfelt plea for peace, with James Bassi's jazz-inflected Quem Pastores Laudavere adding a gentle contemporary note, before the Sixteen's final blaze in Anerio's eight-part Magnificat.
Although I'm loth to mess around with something as classic as an apple turnover, the blackberries and thyme really make a difference here: the berries mottle the stewed apple with rich, crimson juices; thyme lends a gentle, woody note that makes these definitively autumnal.
