In general Tobirama ignored his soul mark. If he did find his soulmate someday then good and if he did not he would hardly pitch a fit. He was the sort of person who didn 't put much stock in fate or destiny. They certainly weren 't on his mind the day he actually did meet his soulmate despite no effort on his part to find them.

Sakura came in to his life like an earthquake, like a landslide that sweeps away everything you have ever known only to replace it with something entirely new. The first time he saw her she was opening the earth with her fist with apparent ease, dropping three men in to a deep chasm and preventing them from attacking Hashirama while he was busy engaged with two other opponents.