Actually its not the words but the actions that show the sincerity of a guy. Girls mostly go for guys who are sincere and decent, guys shudnt come on strong towards girls. A little bit of flirting is fine but too much is just annoying.
So the tip wod b to be urself, down to earth, decent, sincere and dont try toooo hard!! the person who is made for you will eventually come to u. Let nature do its thing
Approach her when its raining. Go close to her and say “I’m gonna skip all that boring stuff and get to the point, wanna go out with me/I like you”
And remember bad guys get all the girls