Adele is known for her honest and open songs, but the 23-year-old singer admits to Cosmopolitan magazine that it's not always the case in real life when she's standing face to face with someone -- especially when it comes to the opposite sex.

"It's so hard for me to share my feelings," she tells the magazine in its December 2011 issue. "I've actually never told a guy that I loved him. I've felt [those words]; I just can't say them. My friend recently convinced me how important it is for guys to know that. I wound up writing letters to all the men I've been with, telling them that I did feel that for them."

All but one of her exes. "I wrote [him] and was like, 'You're a f---ing c---,'" she says in the interview.

At this time in her life, Adele is at peace with not being in a serious relationship and is enjoying her rise to stardom every day. She does get to share those highs with someone special to her. "For now, it's just me and Louie," she smiles, referring to her dachshund.

But at the same time, Adele says part of the reason for not being in a committed relationship is because she still hasn't healed from her last love. "It's bittersweet," Adele says of being single. "I wouldn't give up this success for anything, but at the same time, I'd do anything to be with him. I miss him. I do. And it's hard singing all these songs because it makes me remember how brilliant we were when we were good ... and how tragic it was when we were bad."