I am a girl who strongly believes that you have to be kind to the boys, even if this implies being honest and sending them to the friendzone. And is that men misunderstand kindness with flirting and the friendly relationship gets out of hand. But do not worry, there are very valid reasons to frienzonear a boy and that is 0% your fault.
You hate romanticism (for now)
Maybe you already have enough of the patanes or you just had a break. It doesn't matter! For now you don't want "romantic things." For a boy to convince you, you must change your mindset and this takes time and effort.
You want to be single
This is the most valid reason of all. Especially if you are focused on your study, work or person. It is also good to love and be full of singleness, that makes you an independent woman and who knows what she wants.
You don't find anything in common
Do not idealize with "our type of man", but if you must have a list of characteristics that your partner should have, why? So that at the time of courtship they are not clashing for incompatibility.
There is zero chemistry
I think we all expect that magic or chemistry in a boy to attract us. And no, the movies didn't wash our coconut. That is, as friends they get along great, but you don't feel that spark when he tries to pass that barrier.
You don't want to give it wings
If we add coconut to the matter, it is better to send it to the friendzone than to give it wings. Giving wings is like making him suffer blindly. Sooner or later he will propose to be a bride and groom and the rejection will crush him.
It is the truth, if we friendzone someone it is because we are attracted to absolutely nothing because we consider him ugly as he alone.
You are selective with whom you let into your life
If you were already clear with your reasons and the boy does not understand, obviously it is worth being selective! That is, for me the insistent men are the worst, imagine him as a boyfriend! It will be a total drama the whole relationship.