"Trust" on the other hand, is being able to rely on the strength or integrity of a person. Kumd has loved Saras but Saras has not yet claimed that she can trust him. But still she has. In a moment of weakness she is having some doubts. Not on Saras but on herself!!
That said, i think this is absolutely normal. We all have our share of doubts, fears n insecurities which the other partner has the responsibility to re-instilled!! This is wat makes relationships work n become stronger!!