>>58599495No, it's canonically a one-sided crush on Yellow's part. There's an official Pokespe Encyclopedia book from 2017 with a relationship chart, and the relationship between Red and Yellow is shown to be a one-sided crush. Depending on how you read the chart (since it's not organized that well) Red either just sees Yellow as a friend or he doesn't even remember she exists. But any sane person who has actually read the series wouldn't need a chart to realize Red/Yellow is basically defined by its unrequited nature.
The only confirmed romances in the chart (with red lines representing "love") that aren't one-sided are either Ruby/Sapphire or background character married couples, some who already had children together (with yellow lines representing family ties).