Most Helpful Guys
good question, I've wrestled with this one. It's a matter of the heart, are they giving of the abundance of their heart, or are they really manipulating because they need something. There should at least be a fair exchange and they should be willing to give.
One easy way is to put out small amount of change, see if it disappears. Lend small amount of $, see if it is returned. simple monetary approach.
Also look deep into their eyes, that's the mirror to the soul and will speak volumes. You'll see patterns as you know them... if they have integrity or not. Some people are expert manipulators and promotors though (m or f). If you can ask questions regarding their empathy and compassion for others, that can reveal if they have it. If they don't, it's a red flag to me... how could they be genuinely giving if they don't have empathy:)?
Whether or not they put other people before themselves when physical pain or financial loss comes about.
Most Helpful Girl
You watch and observe their behavior.
Are they nice to you only when things are going well in your life or they need you? Or are they nice and there for you ALL the time? Through the good and bad.
If they don't talk to you when you really need them in your life, or only seem to leech off of you, that's an opportunist!