how will you know if it's true love? Options

[starmoonshore]

a friend of mine asked this question and i just suddenly think and told her... "well, you can tell if you and your significant other love each other. i mean in a sense that you know that you love him and you also know that he loves you too." that's what i told her. but she asked me again, how can you tell if that person really loves you? and i told her, "it's a matter of trust to each other" and then she's like, okay i will accept that answer.

then couple of minutes passed, she replied and said, "there's this one guy i love. he knows that i love him and he tells me that he loves me too. but the problem is, i don't really feel that he loves me. do you think that's true love? i mean, how could you tell? if you asked about our relationship, well, it's a serious relationship but i feel there's something that doesnt make sense at all. i feel it's only one sided, though he said he loves me.. i still don't feel it. what should i do? how would i know?"

that's what my friend asked me but i really have no clue of what to say. so for those people who read this, at least give my friend some advice. thanks a lot!