Most Helpful Guy
It's always hard to tell, I think unless you're a good judge of character you've just gotta assess it over time. Genuine people tend to be fair people, so you won't be asked to do stuff while getting nothing in return, they'll text you half the time and the other half you'll text them, they won't lie to you and bullshit you et cetera.0
Most Helpful Girl
genuine people reach out to you even when there's no occasion (any problem, happy or sad). Listens to you when you talk and give answers that are truly helpful. It's like talking to someone because that person enjoys talking to you and not just for the sake of talking. You would feel that (body language, facial expression, tone of voice). Also, when he/she would give time to you or do more than what you ask or needed in the situation.
You wouldn't know at first if genuine or not but in the long run you would notice changes in action, different character with other people and would barter to his/her advantage most of the time but when you are the one in need there'll be a list of reasons until he/she agrees.0