If someone tells you they love you, check the following out first, then you'll know...
1 Corinthians
13:4 - Love is patient, love is kind. It does not envy, it does not boast, it is not proud.
13:5 - It is not rude, it is not self-seeking, it is not easily angered, it keeps no record of wrongs.
13:6 - Love does not delight in evil but rejoices with the truth.
13:7 - It always protects, always trusts, always hopes, always perseveres.
13:8 - Love never fails. But where there are prophecies, they will cease; where there are tongues, they will be stilled; where there is knowledge, it will pass away.