How To Interpret 患难见真情
I would interpret "患难见真情" as: " true heart (friendship) shows itself in difficult time"

When life is good, everything is fine, you may have a lot of fair weather friends; only in difficult time, you can see whose friendship with you are real.

Similar phrases:

家贫出孝子, 国难见忠臣 (when family is poor, you can see who is a good son; when country is in peril, you can see who are loyal subjects)

路遥知马力, 日久见人心 (long road test the true strength of a horse; long time test the true heart of a person)