As yusaku and Eliot say, "aishiteru" is usually translated as "I love you.". However, "aishiteru" is a verb. So, to be more exact, it's translated as "to love".
Furthermore, "yukidayo" is maybe misstyped. You might mean "suki dayo".
"suki dayo" means "I like you" generally, but it's also translated as "to love" euphemistically a bit.
I think most Japanese(including me) likes the latter because he is too shy to use "aishiteru" for his declaration of love, haha.