Love You, Mean It by Jilly Gagnon

A playful romantic comedy featuring dueling delis, fake dating, a shockingly awesome ex, and just the right amount of amnesia
"[A] delightfully tropey rom-com . . . This is a sweet confection."-Publishers Weekly
Ellie Greco wishes she weren't stuck in Milborough. For a few brief, shining years, she escaped her hometown to pursue her dream career-designing beautiful, elaborate costumes for theater-until her father's death five years ago called her home to run the family's decades-old deli. Yes, she loves the place, but she'd always thought she was meant for more exciting things than stocking the right tinned fish. But when Ellie hears that a local landlord is planning to rent to Mangia, the glitzy gourmet food department store, the very existence of Greco's Deli is suddenly in jeopardy.
She tries to plead her case to Theo Taylor, scion of the property management firm that is about to put her out of business, but their meeting goes from bad (it's not her fault he's infuriating) to worse (no one expects the ceiling to literally fall in).
With Theo out cold, Ellie panics and claims to be his fiancée . . . and almost passes out herself when amnesia means Theo seems to actually believe her. Soon, the effects of the head injury wear off, but Theo proposes that their "engagement" stick around. If they manage to convince enough people, they might both get what they want: an end to the Mangia deal. Ellie doesn't trust him (after all, if Theo Taylor wants it, how can it be good for her?) but seeing no other option, she reluctantly agrees.
And miraculously, the fake engagement seems to be working-even Ted, Theo's shrewd, cold father seems convinced-that is, until Sam, Theo's ex-fiancée, reappears on the scene. Not only does she see through their ruse, but she proposes an arrangement of her own, forcing Ellie to decide between a blossoming friendship, her family legacy, and the burgeoning romance she frankly never asked for.