It's a must to have no secrets and to trust each other in order to have a good relationship
A relationship is positive when there are 0 secrets and 100% trust
(1) It's a must to have no secrets and to trust each other in order to have a good relationship
'it's a must to ~' = 「〜が絶対的」「〜が必要」
'no secrets' ＝「秘密がない」
'trust each other' ＝「お互いを信頼する」
'in order to ~' ＝「〜のためには」
'relationship' ＝「関係」
「良い関係には秘密がないこととお互いへの信頼が絶対的に必要である」
(2) A relationship is positive when there are 0 secrets and 100% trust
'positive relationship' ＝「良い関係性」「関係」
'100% trust' = 「強い信頼」
「強い信頼と秘密がないことで良い関係性は生まれる」
日本 
