Gun aside (which I can't tell if it's a joke or a 'Murican thing), the tone matters a lot. I could totally see my SO doing that in a joking, cutesy manner.
Meanwhile, my parents: Started gushing to each other about how cute Milla Jovovich is when we watched The Fifth Element on family movie night, to the point of making me and my sisters a little uncomfortable.
The characters were drawn in a more stylized way in order to add some levity to the punchline panels. You’ll find a similar technique in anime when the characters become chibi during comedic scenes. This emphasizes the idea that a scene shouldn’t be taken seriously.
The artist probably could’ve gone further with the stylization here to drive the point in harder. Right now it looks more “unfinished” than an obvious style change for comedic effect.
Content that is potentially polarising, allows for virtue signalling, allows judgement of a romantic relationship, meant to be lighthearted......this has a lot of elements to be very successful as internet posted content.
Only ways I can think of is adding in something about sex, weed and /or a dog.
Having my significant other draw a gun on me would end the relationship. Should we both survive this encounter I would take fairly drastic action to make sure we never encounter each other again. I was once in a bit of a dry spell, and I decided to datamine my sex life up to that point to collate what kind of things lead to success, and the thing I realized was more than half of the women I had dated were violent with me. And because sitcoms think that woman slaps man is a punchline, I thought that was normal. I don't accept violence out of a romantic partner anymore and this is a comic depicting a threat of extreme violence between romantic partners.
===
Now seeing that the art style gets more abstract in the last two panels, I won't take the gun literally but more as "she lets it be known that she will make it a major problem if he doesn't comply." Whether it's about her insecurities about her own looks or a desire to control his opinions, the fact that she'd rather threaten to scream or cry or pitch a fit or turn a cold shoulder or make him sleep on the couch or whatever if he doesn't say what she wants him to say rather than talk about it...doesn't really allow much room to build a future with this woman. He'll probably stick around until she stops putting out, probably because she blew up about something.
===
On the third hand, there are ways to play this as flirty and fun, depends on your dynamic together. I strongly suspect the above isn't that, but it can be done.
I tell my husband he's the hottest man around all the time. I even follow it up with "You're even hotter than Jensen Ackles!", so he knows where my standard is.
He usually just rolls his eyes though, so I don't think he takes me very seriously.