Before proposing make sure that you and your partner are both prepared for marriage. There is actually no "best romantic way to propose to your girl". Proposing is a special time in a relationship and should be treated as such.
Find out what your girl likes, ask some of her friends on how she would like to be proposed to, do something personal. Most romantic proposals are done in a private manner than a public manner. Nevertheless, find out what she likes, express yourself in your truest form, do not forget to say how much you love her and how much you want to spend the rest of your life with her.
The most romantic way to propose to a girl is to do it in a private, solemn, and sincere manner. There are a lot of people who do elaborate proposals. They usually spend a lot of money to prove to the world that they can be with that girl forever. There are some women who do not want this.
The most sincere proposals will always be romantic and will always be remembered by women more as compared to those staged proposals that are placed on video. A romantic proposal does not always have to go viral, right? Of course, knowing what the girl wants will also help. Some women would love to be shown off with the use of a highly publicized proposal.