West Germany tries to paint a flexible West and rigid East on missiles

West Germany would like the Hans Mullers of Romania to be able to emigrate without paying a king's ransom. And it would like Bucharest to press Moscow to soften its position in East-West military confrontation.

These two purposes explain West German Foreign Minister Hans-Dietrich Genscher's second trip to Romania within 10 weeks.

The indefatigable traveler Genscher, who returns to Bonn Aug. 11 from his latest three-day visit, has been coy about his second, multilateral goal. But he has been using this as well as every other opportunity to try to convince his public that Bonn and the West are vigorously pursuing any possible compromise on Euromissiles - while the Soviet Union is rigidly rejecting compromise.

This is essential, Mr. Genscher believes, to counter antinuclear demonstrations, to convince the public that it is Moscow and not Washington that is blocking any Euromissile arms control agreement - and that Bonn therefore has no choice but to deploy NATO's planned new missiles beginning in December.

In particular, Genscher - alone among Western leaders - advocates a new East-West renunciation-of-force pledge, possibly at next January's conference on disarmament in Europe in Stockholm. The Soviet Union and its allies recently proposed such a pledge between NATO and the Warsaw Pact.

Western reaction was almost completely negative: Yet another nonaggressive pledge in addition to the United Nations Charter and the 1975 Helsinki Accord, Western chancelleries argued, would achieve nothing concrete and might lull Western Europeans into not supporting the new Euromissile deployments. Genscher, however, wants to pursue this pledge - and to apply it to Afghanistan and Poland.

Genscher's staff has also done nothing to discourage speculation that the foreign minister might be trying to persuade Bucharest to get Moscow to reconsider the ''walk in the woods'' probe in the Euromissile arms control negotiations a year ago.

In that tentative package of US chief negotiator Paul Nitze and Soviet chief negotiator Yuli Kvitsinsky, the Soviet Union would have reduced its three-warhead SS-20s to 75 Europe-targeted systems and 90 Asia-targeted systems, while NATO would have waived the new ballistic Pershing II altogether and would have limited its new cruise missiles to 75 launchers with four missiles each.

Moscow formally rejected this probe last year, and Washington informally rejected it. Cautious attempts by Genscher and by West German Chancellor Helmut Kohl to get the US to revive it (and thus highlight the Soviet rigidity) have been ill-received in Washington.

On the bilateral issue of Romania's extraction of money from emigrants, Genscher has so far been unable to announce any progress. Last spring, Romania rescinded the hefty ''education tax'' it had levied six months earlier on those Jews and ethnic Germans it allows to emigrate. But emigrants have continued to have to pay substantial amounts informally to get their exit visas.