How can I be sure of my sexuality?

You have to know your comfort zone and how you feel sexually. You have to have, for the most part, a sexual attraction to another person. You have to know if you'd be comfortable having sex with a specific gender. Sex isn't everything, but it's a huge part of sexuality.

You can be sure by not labelling it. Love you ever you want to love. If you are attracted romantically to a female then you're attracted to females and if you're sexually attracted to males then you're attracted to males. Sexuality is fluid. It's okay to wake up and feel really gay and feel straight the next.

Just remember that its okay to realize you were wrong about your sexuality. I could have sworn I was straight until I got a HUGE crush on a girl in 9th grade. Give yourself some time to experiment or just be open to the possibilities, because you can't deny your feelings.

Short Answer: You can never be 100% sure. Sexuality is fluid, and can change throughout your life. Experimenting, both with other people, and without can inform you of your preferences. But, that doesn't mean that the way you feel is ever invalid. Period. If you feel attraction to any sex or gender, you have every right to claim that as a part of your sexuality, and no one but you has any say over that or any right to contest it. You are sure when you choose to be sure, and you can question it whenever you like. It's your sexuality, and it's nobody's business but yours.

The certainty comes with time. It took me some years to grow into the idea that I wasn't straight, and now I'm 100% sure that I'm not. You can really be sure if you do self-reflection regularly, this way you'll learn to read your thoughts and feelings faster than before.

By spending time being yourself and finding out and learning about yourself. It just takes time, but you will find your way.

For me, knowing my sexuality was extremely difficult, more so than I think anything in my life has been. It would always fluctuate; sometimes I would really be attracted to girls and not so much guys, but it would flip or I'd even be attracted to both. Occasionally I would stop being attracted to anyone altogether. Labeling your sexuality can be very stressful, I knew it definitely was for me. For a while, I hid under the general term 'bisexual,' although I didn't like how people would assume I just like girls and boys. In reality, I would be attracted to anyone based on personality, not just what they identified as. Take it at your own pace, and if you'd rather not label yourself, that's perfectly fine!

A person's sexuality in my experience may be firm, where one has no questions what-so-ever about the gender or orientation of the people they are sexually attracted to OR it can be fluid and evolving. If you don't feel like you are sure with the one direction you are thinking, use your imagination and "see" what gets your motor running. You should not put pressure on yourself to feel a particular way. You are a unique being, there is no one exactly like you in the entire history of the world and there never will be again, your personality and creativity cannot be boxed into a particular category, so way try to fit your sexuality in a box just to be sure of it?

Your sexuality is your sexuality, you just have to differ the parts of it. Social gender roles, your sexual orientation, your needs, your fetishes and preferences, your imagination and reality. Simple, huh? It's like your body is male, female or hermaphrodite. There are pretty much no other options. Male and female body consist of the inside and outside parts that allows us having all the hormonal balance, sexuality, children too. It isn't anything to be forgot about. It's simple biology. Then there is sexual orientation which would be leading sexual and emotional preference whole your life. Then would be gender role which makes us differently expected and needed in different societies. There could be also sexual identification when you feel man or women despite of your body and have your sexual preference connected to this. And there are preferences, needs, fetishes, which can be just out of a need or to vary the sexual life. We also shouldn't forget in the modern society that most of the people are heterosexual and kind of simple with their gender roles. There are more creative, open minded people, there are also lesbian, bisexual, gay which actually aren't most of our society but some part of it (with all the statistics telling that it could be 3% but it could be also because it was not as openly discussed before as today). Acceptation should go also to the people who understand and need just basic gender roles. While tolerance isn't really acceptation, it's just not going to discuss or interfere something that can't be understand by us, simple letting it be. Thinking that LGBT is most of the society would be blind while most of the society accepting it would be nice. And sexuality contains also being asexual, also different life parts when we need it or can explore it more or less, when we also have different things of mind, as emotional life or everyday's responsibility can make us have different things to do. But as a matter of fact we were born with sexuality and are sexual for a fair part of our life. So if we aren't sure we maybe just aren't it? Or when it takes our time we just have to figure it out. Good luck. :)