A sweet romance trope is when the lover who claims to want big and glamorous and over-the-top settles for the plain, everyday, and ordinary.
Don't get me wrong: big and glamorous and over-the-top has its place. Moulin Rouge, for instance.
But the "realism" (troubling term) of the plain, everyday, and ordinary can be quite effective.
A brilliant example occurs during Niles's proposal to Daphne on Frasier. Niles and Frasier naturally plan a huge, ostentatious evening with musicians and a trumpeter and gourmet food etc. etc. etc. etc.
Daphne arrives with a terrible cold. Niles sits her in front of the fire and then quite spontaneously and quietly proposes. No fuss. Simple sincerity.
The proposal is not only effective and romantic, it illustrates how far Niles has come. He's a guy who likes extravaganzas, but he's learned to give them their place and not use them as ways to prove himself to others.
In manga, my favorite example is No One Loves Me by Yugi Yamada. Reserved, aloof Katsuhiro realizes that his brash lover Masafumi wants to spend Christmas with him, no matter the conditions. And he feels the same. He shows up with leftover cake, greasy chicken, and convenience store champagne.
And it's more than enough!