The phrase "only time" can be synonymously replaced with several other phrases. "Eventual outcome" refers to the idea that given time, everything will eventually result in a certain way. "In due course" suggests that something will happen at the appropriate time, inevitably but not necessarily soon. "Over time" means that a particular change or progression is observed gradually, as time passes. "With the passage of time" is used to describe how things change or transform as time goes by. "In the fullness of time" conveys the idea that something will occur in the precise moment when it is meant to. Overall, these synonyms convey the idea that only patience and waiting will reveal certain truths or outcomes.