How do you know for sure if he's the one?
How do you know for sure if he's the one? What are the signs? How do you avoid messing it up?
The best is to take small steps in his direction. Focus first on fun and excitement. Focus on what you can build on the spot to have a great time together. Stability and all the aspects of a committed relationship come later. The base of what you share must be excitement, love, passion and fun.
The idea that it's either him or nobody is too limiting for you. Some people believe in one single soul mate. I don't. I believe that you have the choice and can accept the fact of experimenting a bit. An experience becomes a mistake only when you repeat it over and over again without learning from it.
Fear of messing it up creates a big pressure. It's performance stress. Now, you don't want to live with a "Damocles sword" on your head for the rest of your life. It is okay to try, experiment and take risks. If you cut yourself from that, life stops altogether!
Accept simply yourself, who you are with what you can call "imperfections". A couple has it's own "imperfections" as well.
The way to mess up the initial stages in dating has to do with lack of respect, talking about politics or religion, forgetting to have fun, talking about your exes, having sex too soon, being demanding or controlling. It's easy to scare off a guy as well when you ask him serious questions about commitment after the second date.
Being clingy, demanding or looking desperate is a great turn off.
Don't be exclusive too soon either. If you spend day an night together when you hardly know each other, you'll get saturated very soon. Give space and refresh yourself by going out with other people. Stay in touch with friends, etc. Give space for the new relationship to breathe and bloom like a flower.
Excess of fire, passion, desire or will power will simply kill the fresh romance, so trust and give it space!
Now go for it!