1. at the time Trump was just a businessman without any access to government secrets.
2. He had plenty of money to be tempted by a spy payoff.
3. Being a spy takes certain ideological basis. It’d very unlikely that Trump shares that type of ideology.
==> Trump doesn’t fit the profile.
This type of smear campaign by the Democrats is meant for the unintelligent and guidable masses.
"...Kompromat is damaging information about a politician, a businessperson, or other public figure, which may be used to create negative publicity, as well as for blackmail, often to exert influence rather than monetary gain, and extortion..."