@yannickq That kind of planning requires omniscience on Rose's part. She was never told Killian's intention.
Logically his counter is simple in that scenario. All he has to do is tell his grandfather that he loves Daisy. He would explain that he took interest in her because of the information she provided in return for her father's debt forgiveness. Only Killian knows what's in his mind. Given that he runs casinos and is a debt collector it's not likely a rumour would phase his grandfather. He'd only use that as a reason to snoop if he'd already planned on doing that. So, unless his grandfather trusts some stranger over his grandchild he'll view this as slander towards his family. However, everyone can be stupid... so who knows.
Since Rose is a bitch and Daisy went running, all upset, to Killian at the end then maybe either:
1) We're headed for Daisy thinking she has to step up her act. She'll think she has to show people 'she's all that' and 'she's in love with Killian' (which doesn't require anything from Killian). That will lead Daisy to go ba-thump and all that jazz (for plot!), or...
2) She's all upset and hubby-kun will take care of it. If this is like standard fare, they'll repeat the sister vs. sister thing... they'll meet again, sister will say "She's a bitch!" and he will say "But you're the bitchier bitch, bitch!" (or he'll stand aside looking awesome while Daisy says it) so sister can go "Just wait! I'll set you up to call me a bigger bitch next time!"... And again, that will lead Daisy to go ba-thump and all that jazz (for plot!)
Or maybe a mixture of both. That's my guess since this was mainly about Rose being a bitch. Priorities! Bitches gotta be bitch slapped.