Feng Qin Yang
Arguably, i'd say this is the safest method to introduce a love interest actually, a girl of unknown origin who is unable to cultivate right now? even if she turns out to be part of a larger family (which going by most cn novels is a probability), she should feel relatively indebted to him. I know I would feel a great deal of debt towards someone who randomly gave me a second chance at life at least. Contrast this to finding a love interest later on who would at the very least have her entire past life prior to meeting him as an unknown.