Upload & Sell: On
A few tweaks, but the salient point I'd make is to look at the color of his shirt. If we look at the area near his waist, we see a blue vs. the white of his cuff or collar/chest area. We can also see a hint of the blue under his lapel (where our flash reaches, but ambient not so much).
Just another example of how our WB is not consistent throughout a scene as we mix light sources (warm vs. cool @ push/pull) and some areas receive more light of one color than that of another color (also in concert with our flash falloff). In that regard, it can be a tricky proposition to assess which area(s) we select for determining our WB. While we pretty much know that the entire shirt is the same color, selecting different portions of the white shirt will render different results (sometimes not so subtle) depending on what light (AI/AR) it is being illuminated by.
This is why I will select four different points on the shirt to see what color they are. A temporary increase of saturation to 50% - 100% can help reveal the color/casts that are present also. I know that they SHOULD all be the same color, so I adjust to try to get them all close to neutral. Rarely can they all be the same (in mixed lighting), so I usually go with 3 out of 4 wins. In this case, the waist area is sacrificial. If I were going to be a bit more picky, I'd selectively edit the lower portion of the shirt and the lapel area independently.
In most snapshot situations, people don't really notice these things as our eye/brain accommodation kicks in. Imo, the WB is an underlining foundation key to bringing your images to life as best you can (followed by other aspects of PP) ... even if you want to warm/cool to artistic preference. Mixed lighting (flash+ambient, sun+shade, flash+shade,etc.) is always an extra level of challenge to assess / contend with.
Looking at the supersat version of the original, we can also see the color variance in his suit and the gray portion of her dress as they also reveal the difference in ambient vs. flash reflecting off of them. So, deciding what area to use as your reference points for "click" type WB setting can be a tricky/subtle proposition in mixed lighting.