There is no real way to tell if another person is in love with you. Of course, they may show you certain signs that may indicate their affections towards you, but only they can tell you how they really feel.
First of all, ask yourself do you love her?
If you aren't sure or even have the slightest bit of doubt in your mind, then why are you trying so hard to make sure she loves you? If you do love her, then you just have to put your faith in her and hope that she will return your love for you. At this point, most people complain that they are going to end up getting hurt and the answer is yes, you may get hurt but at least you will have tried to find love. If they return your love then great! I hope you are very happy together, if not, then you will hurt for a little while but you will find someone else. It is just a sign that you weren't meant to be together.
Eventually, you will find someone that you love beyond belief and who feels the same way about you, and it will feel so much better than any previous relationship. Call me a romantic optimist but that is just my opinion. Don't be afraid to wear your heart on your sleeve because it is better to have loved and lost than never to have loved before, as Alfred Lord Tennyson once said.
Are there any signs to look for to know if my girlfriend really loves me?
You can look for as many signs as you want and analyse her behaviour, but all it comes down to is if she tells you she loves you, then you just need to trust that she does. Because if she has said that she does, then it is probably true. If you start to doubt her, then you'll doubt the relationship and if you put too much pressure on a relationship then you will just make her want to walk away, it's unfortunate but true