Because Yamato will understand how important it is to be close to Momo in order for wano to be safe.
Yamato didn't even know Momo was alive when she told Luffy about the explosion cuffs 😭😭 Yamato told ace that if she didn't have the explosion cuffs on she will join him out to the seas, and Kaido say that Yamato took the explosion cuff off and if she thinks she going to leave like that 😭😭😭 where do you that bullshit answer from all? It was the chain that was stopping Yamato from leaving Wano 😭😭