The `Water for Elephants` actor - who is dating his `Twilight` co-star Kristen Stewart - thinks people can fall for each other as soon as they meet and says if there`s not an initial attraction, it`s hard to ever develop feelings for that person.
He told MTV News: "I think people can fall in love at firstsight. I think pretty much all people who love each other, had some kind of thing at firstsight. I mean, there has to be some kind of moment where you, like, feel a different energy around someone.
"Generally, if you don`t notice someone ever, you`re probably not going to fall in love with them."
As well as believing in love at firstsight, the 24-year-old heartthrob recently revealed he has a "romantic soul" and could never have sex with someone he didn`t love.
Robert said: "There is the idea of the saving love, I believe it. I`m not mushy but I have a romantic soul. Having grown up with two older sisters I have a deep respect for women. Sex and feeling for me go hand in hand.
"I`m not interested in casual relationships, I need to know people."