It is important to ensure that she is actually staring at you.
When you like someone, it can be easy to become misdirected.
In other words, you may believe that she is staring at you because that is what you want to see.
Due to the fact that you like her, your brain can trick you into believing that she was staring at you when in fact she was looking past you or at something else in your general direction.
So, it is very important that you truly establish that she is actually still staring at you as opposed to misguiding yourself into believing what may actually not be true.
If you believe that she is truly still staring at you after having told you that she isn’t sure if she likes you, she may be doing it because she is quite shy.
She may not quite know how to handle you or may not have much experience in romantic relationships.
She may be allowing this lack of experience and anxiety to get the best of her.
She is unable to give you a definitive answer because she may fear that she won’t be able to live up to your expectations or she will screw it up in some way.
If you know that this is a girl who hasn’t had that many relationships, this could be your reason.
She isn’t that grounded in who she is as a person and how she may affect a relationship.
She may have anxiety.
Since she may feel this way, she may want to have some more time to observe you.
She may still be staring at you because she wants to observe your behavior.
The more she stares at you, the more she observes how you carry yourself and what you tend to talk about with others.
She may be trying to use these moments as her guide.
She may want to observe you in these moments so that she can come to a decision on whether your personality would connect or work with her own.
Again, a girl who is shy and lacks experience in dating would be the most likely person to use this kind of approach.
She would want to make it as easy on herself as possible if she were to truly take the next step in dating you.
If she were able to observe your demeanor during this time, she would be able to gather up enough information to make her decide on what to do. Hence, she is being cautious.
A girl who is still staring at you after telling you that she is not sure if she likes you may be hoping that you are patient with her.
She may be hoping that you give this thing more time.
When she stares at you, she may be trying to send the signal that she may be interested in dating you in the future but she just wants to get to know you better first.
She may not come right out and tell you this but may be hoping that you work on building a friendship with her first.