This just came in but I’m answering it because I know the answer off the top of my head and it’s a simple one.
父さんはいつも武器に『リズ ラブ』とかいう 名前を入れて気まずかった…
…もしかして、もう同じことしてるのか？ その武器も『リズ ラブ』なのか？ うわー…
It says literally, in Katakana, “Liz rabu” and if you’ve hung around animanga fandom long enough you’d probably know that rabu is how you write the loanword from English for love and yeah this inscription is at least as silly as like, “I <3 Lissa”.
I do think it’s worth noting that it’s a bit sillier than “I love Lissa,” though I suppose it could be argued that the very act of writing such a phrase on your weapon makes it silly.
(Incidentally, an allusion to this moment in Infinite Regalia was lost in localization. This writeup is not mine but it is accurate.)