There are thousands of ways to ask someone to be your Valentine. You might give them a Valentine's Day card that asks them or you might write a letter or even send some chocolates. You could also ask someone to be your Valentine by creating a romantic gesture. You could give that person several real roses and one artificial rose. Then tell the person that you will love him or her until that last flower dies. Ask them to be your Valentine in a poem, in a song, or even in a skit or funny joke.