The phrase "romantic notion" refers to an idea or belief that is driven by idealistic or sentimental views, often related to love, relationships, or passionate feelings. Full definition
We always wanted to build our own home, with romantic notions of mature fruit trees and a vegetable patch, but didn't think it was realistic in the area where we settled. (passivehouseplus.ie)
To capture a robust sense of moral purpose, contemporary notions about self - fulfillment must be discarded along with romantic notions about inherent goodness. (religion-online.org)
As romantic a notion as that might be, eternity is a very long time. (religion.blogs.cnn.com)