Strike while the iron is hot

[Lina]

Possibly not a good suggestion, but a more passive way to do it, perhaps a bit easier for you, is not to actually physically give it to her, but to leave it somewhere where she's bound to find it when you're not around. Maybe one day you both have off, leave it on the pillow and leave early in the morning to go somewhere else for a while. (With an explanatory addition to the note, of course.)

Or at least some way you don't have to confront her then and there, if that's what you're concerned about.