Each of us defines love in our own way. We tell ourselves if she/he loves me then they will say blah blah, they will act this way, they will bend over backwards to please me, they will do the best they can to ensure that I am happy....etc However in reality no two people are the same nor do they think and believe the same. Some people are content with simply hearing the words, "I love you". Others observe behavior and actions.
First of all YOU have to define what "Love" is in YOUR mind. It's the only way you can identify it when you see it. Secondly you must learn what love means to your significant other.
A woman may feel loved if her man sends her flowers, poems, candy, plans romantic getaways, helps around the house, and supports her goals.....(Until she learns he does the same thing for EVERY girl he dates!)
Now she feels love is not about words or actions! In order for her to feel loved she has to KNOW he is doing something "special" for her. For this woman to feel loved she has to believe she is "the exception". Her man has to top whatever he has offered his exes. She measures his love by his level of "sacrafice".
Anytime we ask if someone "really loves us" it's because we don't believe they do. Perception is reality. Not believing equals not Trusting. You have to trust your own instincts and if something tells you this person is not "trustworthy" move on. Not listening to yourself leads to regrets.
Last but not least there are those of us (who do not love ourselves) and therefore have a real difficult time believing anyone else could love us. Until this individual learns to love themself and raise their self-esteem they will never ever really believe someone loves them. In order accept love one must believe she/he is loveable.