Sienna Miller sounds like a woman in love in the new issue of the U.K.'sElle, where she can't stop gushing about her boyfriend, Rhys Ifans. "When his name is mentioned, it makes me smile like a fool because I instantly think of him and it makes me happy," admits the actress. "He does just make me happy." And a note to all men out there — the way to Sienna's heart may be through a big belly laugh. "I totally love Rhys but most of all, he's my best friend," says Sienna. "He makes me laugh. Not just a little laugh — he can completely floor me laughing." But don't expect wedding bells just yet. "No ring. I'm so happy with our relationship as it is. It has always been incredibly easy and uncomplicated."