User blog comment:B214/Chapter 510: Natsu's Heart/@comment-27337151-20161114193109/@comment-7418318-20161114201250

They were closer due to having met much sooner in the X-sevenhundreds, but we don't know if they were also closer back 400 years ago.

To me it seems that back then Wendy was little more than a crybaby with little to no self-confidence. Not exactly a mental image suited to give morale support. For all his faults, confidence is one thing that Sting certainly did not lack (except for the gap between his thrashing in the GMG and relieving Jiemma of his post, but that came much later).